PSI - Issue 15

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M. Abdulsalam et al. / Procedia Structural Integrity 15 (2019) 2–7 Abdulsala and Feng / Structural Integrity Procedia 00 (2019) 000–000 Abdulsalam and Feng / Structural Integrity Procedia 00 (2019) 000–000 Abdulsalam and Feng / Structural Integrity Procedia 00 (2019) 000–000 Abdulsalam and Feng / S ructural Integrity Procedia 00 (20 9) 0 0–000 Abdulsalam and Feng / Structural Integrity Procedia 00 (2019) 000–000 Abdulsalam and Feng / Structural Integrity Procedia 00 (2019) 000–000

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were firstly collected with no plaque as a healthy case and the measurements were taken proximal to the plaques. The flow rate and wall movement data were collected simultaneously and sent it to the computer. These data were analyzed by Matlab version 16. 4. Results 4.1. The measured diameter and velocity The measured velocity and diameter for the healthy one (no plaque), unstable plaque and stable plaque are shown in Fig.2 a and b, respectively. It is clear that the higher amplitudes of diameter waveforms were generated in the arteries with the plaques attached, while healthy artery with no plaque has the lowest amplitude of the diameter waveforms. As is expected, the stable plaque generated the highest amplitude of the arterial waveform, while the amplitude of the diameter waveform in the artery with the unstable plaque is less than that with the stable plaque. Similar pattern was also found for the velocity arterial waveform although the difference between three types of arterial system is not very significant. 4.2. The forward diameter and velocity WIA is used to separate the measured pressure, velocity and diameter into the forward and backward components for three types of arterial-plaque system (Fig.3). The forward velocity amplitude of the stable plaque that generated from the heart (ventricle) is slightly higher than that of unstable plaque (0.553 m/s via 0.533 m/s). Similarly, the forward diameter amplitude of stable plaque is also slightly higher than that of unstable plaque (1.04 mm via 0.96 mm). 4.3. The backward diameter and velocity The backward waves which produced from the reflections are shown in Fig. 4 a and b. It was observed from the figures that the backward velocity and diameter of soft plaque are higher than those for hard plaque are. This phenomenon is opposite to our prediction as the hard plaque should have higher backward reflection than the soft plaque because of their stiffness. 5. Discussion This study investigated two types of plaques: the FC and TCFA plaques, which represent the hard plaque and soft plaque, respectively. Configuration of these two artificial plaques were referred from the previous studies regarding the plaque characteristics and properties by Guo et al. (2013), Teng et al ., (2014) and Butcovan et al. (2016). The data was collected after five minutes of starting the experiment. Each plaque was tested three times in order to ensure the reproducibility. It is as expected that the stable plaques with the higher proportions of Ca is linked with the higher amplitude of the measured diameter, whereas the unstable plaques with the more percentage of lipid core is related to the lower amplitude of the measured diameter. The visible differences of the measured velocity waveforms were observed for two types of the arterial-plaques system with the lowest velocity amplitude occurring at the arterial system with the stable plaque. This means that stable plaques generated the stronger reflected waves, leading to the higher amplitude of the arterial diameter waveform and lower amplitude of the velocity waveforms. The observations from Fig. 3a shows that the forward velocity in hard plaque is slightly higher than soft plaque. This observation could be explained as the further reflection of the reflected wave was occurring at the inlet of the system, which led to the increase of the velocity. Likewise, the forward diameter amplitude (Fig. 3b) in hard plaque is slightly higher than in soft plaque with the same reason. The amplitude of backward waveform in the arterial system with hard plaque is expected to be higher than soft plaque because the stiffness of the arterial hard plaque is higher than soft plaque which supposed to produce higher reflection. It has been observed that the backward reflection amplitude of the soft plaque in velocity and diameter is higher than hard plaque (Fig. 4 a and b). These results do not meet our expectation. The reason of this phenomenon could be from further re-reflections from the inlet tube or because the material properties of the artificial artery of the hard plaque is different from the one that used in the soft plaque which do need further investigations. ere firstly collected ith no plaque as a healthy case and the easure ents ere taken proxi al to the plaques. The flow rate and wall movement data were collected si ultaneously and sent it to the co puter. These data were analyzed by Matlab version 16. 4. Results 4.1. The measured dia eter and velocity The measured velocity and dia eter for the healthy one (no plaque), unstable plaque and stable plaque are shown in Fig.2 a and b, respectively. It is clear that the higher amplitudes of diameter waveforms were generated in the arteries ith the plaques attached, hile healthy artery ith no plaque has the lo est a plitude of the dia eter avefor s. s is expected, the stable plaque generated the highest amplitude of the arterial waveform, while the amplitude of the diameter waveform in the artery with the unstable plaque is less than that ith the stable plaque. Similar pattern as also found for the velocity arterial avefor although the difference between three types of arterial system is not very significant. 4.2. The forward dia eter and velocity WIA is used to separate the measured pressure, velocity and diameter into the for ard and back ard components for three types of arterial-plaque system (Fig.3). The forward velocity amplitude of the stable plaque that generated from the heart (ventricle) is slightly higher than that of unstable plaque (0.553 /s via 0.533 /s). Similarly, the forward diameter amplitude of stable plaque is also slightly higher than that of unstable plaque (1.04 mm via 0.96 mm). 4.3. The backward diameter and velocity The backward aves hich produced fro the reflections are sho n in Fig. 4 a and b. It was observed from the figures that the back ard velocity and dia eter of soft plaque are higher than those for hard plaque are. This phenomenon is opposite to our prediction as the hard plaque should have higher backward reflection than the soft plaque because of their stiffness. 5. Discussion This study investigated two types of plaques: the FC and TCFA plaques, hich represent the hard plaque and soft plaque, respectively. Configuration of these two artificial plaques were referred from the previous studies regarding the plaque characteristics and properties by Guo et al. (2013), Teng et al ., (2014) and Butcovan et al. (2016). The data was collected after five minutes of starting the experi ent. Each plaque as tested three times in order to ensure the reproducibility. It is as expected that the stable plaques with the higher proportions of Ca is linked with the higher amplitude of the measured diameter, whereas the unstable plaques with the more percentage of lipid core is related to the lower amplitude of the measured diameter. The visible differences of the measured velocity avefor s were observed for two types of the arterial-plaques system with the lowest velocity amplitude occurring at the arterial syste ith the stable plaque. This means that stable plaques generated the stronger reflected waves, leading to the higher amplitude of the arterial dia eter waveform and lower amplitude of the velocity waveforms. The observations from Fig. 3a shows that the forward velocity in hard plaque is slightly higher than soft plaque. This observation could be explained as the further reflection of the reflected wave was occurring at the inlet of the system, which led to the increase of the velocity. Likewise, the forward diameter amplitude (Fig. 3b) in hard plaque is slightly higher than in soft plaque with the same reason. The amplitude of backward waveform in the arterial system with hard plaque is expected to be higher than soft plaque because the stiffness of the arterial hard plaque is higher than soft plaque hich supposed to produce higher reflection. It has been observed that the backward reflection amplitude of the soft plaque in velocity and diameter is higher than hard plaque (Fig. 4 a and b). These results do not meet our expectation. The reason of this phenomenon could be from further re-reflections from the inlet tube or because the aterial properties of the artificial artery of the hard plaque is different from the one that used in the soft plaque which do need further investigations. were firstly collected with no plaque as a healthy case and the measurements were taken proximal to the plaques. he flo rate and all ove ent data ere collected simultaneously and sent it to the computer. hese data ere analyzed by atlab version 16. 4. Results 4.1. The easured diameter and velocity he easured velocity and diameter for the healthy one (no plaque), unstable plaque and stable plaque are shown in Fig.2 a and b, respectively. It is clear that the higher amplitudes of diameter waveforms were generated in the arteries with the plaques attached, while healthy artery with no plaque has the lowest amplitude of the diameter waveforms. As is expected, the stable plaque generated the highest amplitude of the arterial wavefor , hile the a plitude of the diameter waveform in the artery with the unstable plaque is less than that with the stable plaque. Similar pattern was also found for the velocity arterial waveform although the difference between three types of arterial system is not very significant. 4.2. The forward diameter and velocity WI is used to separate the easured pressure, velocity and diameter into the for ard and back ard co ponents for three types of arterial-plaque syste (Fig.3). he for ard velocity a plitu e of the stable plaque that generated from the heart (ventricle) is slightly higher than that of unstable plaque (0.553 m/s via 0.533 m/s). Similarly, the forward diameter amplitude of stable plaque is also slightly higher than that of unstable plaque (1.04 mm via 0.96 mm). 4.3. The back ard dia eter and velocity The backward waves which produced from the reflections are shown in Fig. 4 a and b. It was observed from the figures that the backward velocity and diameter of soft plaque are higher than those for hard plaque are. his phenomenon is opposite to our prediction as the hard plaque should have higher back ard reflection than the soft plaque because of their stiffness. 5. Discussion This study investigated t o types of plaques: the F and F plaques, which represent the hard plaque and soft plaque, respectively. onfiguration of these two artificial plaques were referred from the previous studies regarding the plaque characteristics and properties by Guo et al. (2013), Teng et al ., (2014) and Butcovan et al. (2016). The data was collected after five inutes of starting the experiment. Each plaque was tested three times in order to ensure the reproducibility. It is as expected that the stable plaques with the higher proportions of a is linked with the higher amplitude of the measured diameter, whereas the unstable plaques with the ore percentage of lipid core is related to the lo er a plitude of the easured dia eter. he visible differences of the measured velocity waveforms ere observed for two types of the arterial-plaques system with the lo est velocity amplitude occurring at the arterial system with the stable plaque. This means that stable plaques generated the stronger reflected waves, leading to the higher amplitude of the arterial diameter waveform and lower amplitude of the velocity waveforms. The observations from Fig. 3a shows that the forward velocity in hard plaque is slightly higher than soft plaque. This observation could be explained as the further reflection of the reflected wave was occurring at the inlet of the system, which led to the increase of the velocity. Likewise, the forward diameter amplitude (Fig. 3b) in hard plaque is slightly higher than in soft plaque with the same reason. he amplitude of backward aveform in the arterial system with hard plaque is expected to be higher than soft plaque because the stiffness of the arterial hard plaque is higher than soft plaque which supposed to produce higher reflection. It has been observed that the back rd reflection a plitude of the soft plaque in velocity and diameter is higher than hard plaque (Fig. 4 a and b). hese results do not eet our expectation. he reason of this ph no enon could be fro further re-reflections fro the inlet tube or because the material properties f the artificial artery of the hard plaque is different fro the one that used in the soft plaque hich do need further investigations. were firstly collected with no plaque as a healthy case and the measurements were taken proximal to the plaques. The flow rate and wall movement data were collected si ultaneously a d sent it to the computer. These data were analyzed by Matlab version 16. 4. Results 4.1. The measured dia eter and velocity The measured velocity and diameter for the healthy one (no plaque), unstable plaque and stable plaque are sho n in Fig.2 a and b, respectively. It is clear that the higher a plitudes of dia eter avefor s ere generated in the arteries with the plaques attached, while healthy artery with no plaque has the lowest amplitude of the dia eter avefor s. s is expected, the stable plaque generated the highest a plitude of the arterial waveform, while the amplitude of the diameter waveform in the artery with the unstable plaque is less than that ith the stable plaque. Si ilar pattern as also found for the velocity arterial wavefor although the difference bet een three types of arterial syste is not very significant. 4.2. The forward diameter and velocity IA is used to separate the measured pressure, velocity and dia eter into the forward and backward components for three types of arterial-plaque system (Fig.3). The forward velocity amplitude of the stable plaque that generated fro the heart (ventricle) is slightly higher than that of unstable plaque (0.553 m/s via 0.533 /s). Si ilarly, the for ard diameter a plitude of stable plaque is also slightly higher than that of unstable plaque (1.04 via 0.96 ). 4.3. The backward diameter and velocity he back ard waves which produced from the reflections are shown in Fig. 4 a and b. It as observed fro the figures that the backward velocity and diameter of soft plaque are higher than those for hard plaque are. This pheno enon is opposite to our prediction as the hard plaque should have higher backward reflection than the soft plaque because f their stiffness. 5. iscussion his study investigated two types of plaques: the FC and F plaques, which represent the hard plaque and soft plaque, respectively. Configuration of these t o artificial plaques ere referred fro the previous studies regarding the plaque characteristics and properties by uo et al. (2013), Teng et al ., (2014) and Butcovan et al. (2016). he data as collected after five minutes of starting the experiment. ach plaque as tested three ti es in order to ensure the reproducibility. It is as expected that the stable plaques ith the higher proportions of Ca is linked ith the higher a plitude of the easure dia eter, hereas the unstable plaques ith the ore percentage of lipid core is related to the lower amplitude of the measured diameter. The visible differences of the easured velocity avefor s ere observed for t o types of the arterial-plaques syste ith the lo est velocity a plitude occurring at the arterial syste ith the stable plaque. his eans that stable plaques g nerated the stronger reflected aves, leading to the higher a plitude of the arterial dia eter avefor and lo er a plitude of the velocity avefor s. he observati ns fro Fig. 3a sho s that the for ard velocity in hard plaque is slightly higher than soft plaque. his observation could be explained as the further reflection of the reflected ave as occurring at the inlet of the syste , hich led to the increase of the velocity. ike ise, the for ard dia eter a plitude (Fig. 3b) i hard plaque is slightly higher than in soft plaque ith the sa e reason. The a plitude of back ard wavefor in the arterial system with hard plaque is expected to be higher than soft plaque because the stiffness of the arterial hard plaque is higher than soft plaque hich supposed to produce higher reflection. It has been observed that the backward reflection amplitude of the soft plaque in velocity and dia eter is higher than hard plaque (Fig. 4 a and b). hese results do not eet our expectation. he reason of this phenomenon could be from further re-reflections from the inlet tube or because the material properties of the artificial artery of the hard plaque is different from the one that used in the soft plaque which do need further investigations. were firstly collected with no plaque as a healthy case and the measurements were aken proximal to the plaques. The flow rate and wall movement data were collected simultaneously and sent it to the computer. These data were analyzed by Matlab version 16. 4. Results 4.1. The measured diameter and velocity The measured velocity and diameter for the healthy one (no plaque), unstable plaque and stable plaque a shown in Fig.2 a and b, resp ctively. It is clear that the higher amplitudes of diameter waveforms were generated in the arteries with the plaques attached, while healthy artery with no plaque has the lowest amplitude of the diameter waveforms. As is expected, the stable plaque gen rated the highest amplitude of the arterial waveform, while the amplitude of the diameter waveform in th artery with the unstable plaque is less than that with the stable plaque. Simil r pattern was also found for the velocity arterial waveform although the difference between three types of arterial system is not very significant. 4.2. The forward diameter and velocity WIA is used to separate the measured pressure, velocity and diameter into the forwar and backward components for thr e types of arterial-plaque sy tem (Fig.3). The forw rd velocity amplitude of the stable plaque that generated from the heart (ventricle) is slightly higher than that of unstable plaque (0.553 m/s via 0.533 m/s). Similarly, the forward diameter amplitude of stable plaque is also slightly higher than that of unstable plaque (1.04 mm via 0.96 mm). 4.3. The backward diameter and velocity The backward waves which produced from th reflections are shown in Fig. 4 a and b. It was observed from the figures that the backward velocity and diameter of soft plaque are high r than those for hard plaque are. This phenomenon is opposi e to our prediction as the hard plaque should have higher backward reflection than the soft plaque because of their stiffness. 5. Discussion This study investigated two types of plaques: the FC and TCFA plaques, which r present t e hard plaque and soft plaque, respectively. Configuration of these two artificial plaques were referred from the previous studies regarding the pl que chara ristics and properties by Guo et al. (2013), Teng et al ., (2014) and Butcovan et al. (2016). The data was collected after five minutes of starting the exp riment. Each plaque was tested three times in order to ensure the reproducibility. It is as expect th t the stable pl ques with the higher proportions of Ca is linked with the higher amplitude of the me sured iame er, whereas the unstable plaques with the more percent ge of lipid core is related to the lower amplitude of the measured di meter. The visible differ nces of the measured velocity waveforms were observed for two types of the arterial-plaques system wi h the lowest velocity amplitude occurring at the arteri l sys em with the stab e plaque. This means that stable plaques generated the str nger refle ted waves, leading to the higher amplitude of the arterial diameter waveform and lower amplitude of the veloc ty w vef rms. Th observations from Fig. 3a shows that the forward ve o ity in hard plaqu is slightly higher than soft plaque. This observation could be xplained as further reflection of the reflecte wave was occurring at the inlet of the system, which led to t e increase of th velocity. Lik wise, the forward diameter amplitude (Fig. 3b) in hard plaque is slightly higher than in soft plaque with the sa e reason. The amplitude of backward waveform in the arterial system with hard plaque is expected to be higher than soft plaque because the stiff ess of the arterial hard pl que is higher than soft plaque which supposed to produce higher reflect on. It s been observed that the backward reflection amplitude of the soft plaque in velocity and diamet r is higher than hard plaque (Fig. 4 a and b). These results do not meet our expectation. The reason f t is phenomenon c uld be from further re-reflections from the inlet tube or because the material properties of the artificial artery of the hard plaque is different from the one that used in the soft plaque which do need further investigations. were firstly collected with no plaque as a healthy case and the measureme ts were aken proximal to th plaques. The flow rate and wall movement data were collected simultaneously and sent it to the computer. These data were analyzed by Matlab version 16. 4. Results 4.1. The measured diameter and velocity The measured velocity and diameter for the healthy one (no plaque), unstable plaque and stable plaque are shown in Fig.2 a and b, resp ctively. It is clear that the igher amplitudes of dia e er wav for s wer generated in he arteries with the plaqu s attac ed, while healthy art y with no plaque has the lowes amplitude of the diameter wavefor s. As is expected, the stable plaque gen ated the highest amplit de of the rteri l aveform, while the amplitude of the diameter waveform in th artery with the unstable plaque is less than that with the stable plaque. Similar pa tern was also found for the velocity arterial waveform although the difference between three types of arterial system is not very significant. 4.2. The forward diameter and velocity WIA is used to separate the me sured pre sur , velocity and diameter into the forward and backward componen s for three types of arterial-plaque system (Fig.3). The forward velocity amplit de of the stable plaque that generated from the heart (ventricle) is slightly higher than that of unstable plaque (0.553 m/s via 0.533 m/s). Similarly, the forward diameter amplitude of stable plaque is also slightly higher than that of unstable plaque (1.04 mm via 0.96 mm). 4.3. The backward diameter and velocity The backward waves which produced from the reflections are shown in Fig. 4 a and b. It was observed from t e figures that the backward velocity and diameter of soft plaque are igher than those for hard plaque are. This phenomenon is opp site to our prediction as the hard plaque should have higher backward reflection than the soft plaque because of their stiffness. 5. Discussion This study inves gated two types of plaqu s: the FC and TCFA plaques, which represent the hard plaque and soft plaque, respectively. Configuration of these two artificial plaques were referred from the previous studies regarding the plaque haracteristics and properties by Guo e al. (2013), Teng et al ., (2014) and Butcovan et al. (2016). The data was collected after five minutes of starting the exp riment. Each plaque was tested three times in order to ensure t e reproducibility. It is as expecte th t the stable pl ques with the higher proportions of Ca is linked with the higher amplitude of the measured diameter, whereas the unstable plaques with the more percentage of lipid core is related to the lower amplitude of the measured diameter. The visible differences of the measured velocity waveforms were observed for two types of the art rial-plaques sy tem with the owest v locity amplitude occurring at the arterial sys em with the stable plaque. This means that stable plaques gen ated the stronger r flec ed waves, leading to the higher amplitude of the arterial diameter waveform and lower amplitude f the velocity waveforms. The observations from Fig. 3a shows that the forward ve ocity in hard plaque is slightly higher than soft plaque. Thi observation could be explained as the further reflection of the reflected wav was occurring at the i let of the system, which led to the increase of the velocity. Likewise, the forward diameter amplitude (Fig. 3b) in hard plaque is slightly higher than in soft plaque with the sa e reason. The amplitude of backward waveform in the arterial system with hard plaque is expected to be higher than soft plaque because the stiff ess of the arterial hard pl que is higher than soft plaqu which supposed to produce h gher reflection. It has been observed that the backward r fl ction amplitude of the soft plaque in velocity and diameter is higher than hard plaque (Fig. 4 a and b). These results do not meet our expectation. The reason of t is phenomenon c uld be from further re-reflections from the inlet tube or because th material properties of the artific al artery of the hard plaque is different from the one that used in the soft plaque which do need further investigations.