Evaluation of Atrial Septal Defect Using Real-time Three-dimensional Echocardiography:Comparison with Surgical Findings

The present study evaluated the application of three dimensional echocardigraphy （3DE） in the diagnosis of atrial septal defect （ASD） and the measurement of its size by 3DE and compared the size with surgical findings. Two-dimensional and real-time three dimensional echocardiography （RT3DE） was performed in 26 patients with atrial septal defect, and the echocardiographic data were compared with the surgical findings. Significant correlation was found between defect diameter by RT3DE and that measured during surgery （r=0.77, P〈0.001）. The defect area changed significantly during cardiac cycle. Percentage change in defect size during cardiac cycle ranged from 6%-70%. Our study showed that the size and morphology of atrial septal defect obtained with RT3DE correlate well with surgical findings. Therefore, RT3DE is a feasible and accurate non-invasive imaging tool for assessment of atrial septal size and dynamic changes.

Application of real-time 3d echocardiography in mitral valve repair for replacement of chordae tendineae

Objective To investigate the surgical technique and outcomes of replacement of chordae tendineae in mitral valve repair,and evaluate the value of real-time three-di-mensional transesophageal echocardiography in the perioperative period. Methods Thirty-one patients with mitral valve prolapse underwent mitral valve repair using chordae tendineae replacement concomitant with implantation

Evaluation of Right Ventricular Volume and Systolic Function by Real-time Three-dimensional Echocardiography

The optimal plane for measurement of the right ventricular (RV) volumes by real-time three-dimensional echocardiography (RT3DE) was determined and the feasibility and accuracy of RT3DE in studying RV systolic function was assessed. RV “Full volume” images were acquired by RT3DE in 22 healthy subjects. RV end-diastolic volumes (RVEDV) and end-systolic volumes (RVESV) were outlined using apical biplane, 4-plane, 8-plane, 16-plane offline separately. RVSV and RVEF were calculated. Meanwhile tricuspid annual systolic excursion (TASE) was measured by M-mode echo. LVSV was outlined by 2-D echo according to the biplane Simpson's rule. The results showed: (1) There was a good correlation between RVSV measured from series planes and LVSV from 2-D echo (r=0.73; r=0.69; r=0.63; r=0.66, P<0.25—0.0025); (2) There were significant differences between RVEDV in biplane and those in 4-, 8-, 16-plane (P<0.001). There was also difference between RV volume in 4-plane and that in 8-plane (P<0.05), but there was no significant difference between RV volume in 8-plane and that in 16-plane (P>0.05); (3) Inter-observers and intro-observers variability analysis showed that there were close agreements and relations for RV volumes (r=0.986, P<0.001; r=0.93, P<0.001); (4) There was a significantly positive correlation of TASE to RVSV and RVEF from RT3DE (r=0.83; r=0.90). So RV volume measures with RT3DE are rapid, accurate and reproducible. In view of RV's complex shape, apical 8-plane method is better in clinical use. It may allow early detection of RV systolic function.

Role of real-time three-dimensional transesophageal echocardiography in mitral valve repair

Background and objective Pre-operative assessment of mitral valve (MV) anatomy is essential to surgical design in patients undergoing MV repair.Although 2-dimensional (2D) echocardiography provides precise information regarding MV anatomy,RT-3D TEE could increase the understanding of MV apparatus and individual scallop identification.We aimed to investigate the value of RT- 3DTEE in MV repair.Methods RT-3DTEE was performed in six patients with mitral valve prolapse (MVP) by using Philips 1E33 with X7-2t probe.Preoperative RT-3DTEE studies were compared with surgical findings in patients undergoing surgical mitral valve repair,and quantitative evaluation was performed by QLab 6.0 software before and after surgical mitral valve repair.Results RT- 3DTEE could display dynamic morphology of MV,the location of prolapse,and spatial relation to the surrounding tissue.It could provide surgical views of the valves and the valvular apparatus.These results were consistent with surgical findings.The quantitative evaluation before and after surgical MV repair indicated that anterolateral to posteromedial diameter of annulus,anterior to posterior diameter of annulus,perimeter of annulus,and area of annulus in projection plane were significantly smaller after operation compared with those before operation (P【0.05).The length of posterior leaflet,the area of anterior and posterior leaflet,the maximal prolapse height,the volume of leaflet prolapse and the length of coaptation in projection plane were significantly reduced after operation (P【0. 05).Conclusion RT-3DTEE is a unique new modality for rapid and accurate evaluation ofmitral valve prolapse and mitral valve repair.

Evaluation of the Left Ventricular Remodeling in Patients with Myocardial Infarction after Revascularization with Intravenous Real-time Myocardial Contrast Echocardiography

In order to evaluate the left ventricular remodeling in patients with myocardial infarction after revascularization with intravenous real-time myocardial contrast echocardiography （RT-MCE）, intravenous RT-MCE was performed on 20 patients with myocardial infarction before coronary revascularization. Follow-up echocardiography was performed 3 months after coronary revascularization. Segmental wall motion was assessed using 18-segment LV model and classified as normal, hypokinesis, akinesis and dyskinesis. Myocardial perfusion was assessed by visual interpretation and divided into 3 conditions： homogeneous opacification=l; partial or reduced opaciflcation or subendocardial contrast defect=2; constrast defect=3. Myocardial perfusion score index （MPSI） was calculated by dividing the total sum of contrast score by the total number of segments with abnormal wall motion. Twenty patients were classified into 2 groups according to the MPSI： MPSI≤I.5 as good myocardial perfusion, MPSI〉1.5 as poor myocardial perfusion. To assess the left ventricular remodeling, the following comparisons were carried out： （1） Comparisons of left ventricular ejection fraction （LVEF）, left ventricular end-systolic volume （LVESV） and left ventricular end-diastolic volume （LVEDV） before and 3 months after revascularization in two groups;（2） Comparisons of LVEF, LVESV and LVEDV pre-revascularization between two groups and comparisons of these 3 months post-revascularization between two groups; （3） Comparisons of the differences in LVEF, LVESV and LVEDV between 3 months post-and pre-revascularization （ALVEF, ALVESV and ALVEDV） between two groups; （4） The linear regression analysis between ALVEF, ALVESV, ALVEDV and MPSI. The results showed that the LVEF obtained 3 months after revascularization in patients with MPSI〉1.5 was obviously lower than that in those with MPSI〈1.5. The LVEDV obtained 3 months post-revascularization in patients with MPSI〉1.5 was obviously larger than that in those with MPSI≤1.5 （P=0.002 and 0.04）. The differences in ALVEF and ALVEDV between patients with MPSI〉I.5 and those with MPSI≤1.5 were significant （P=0.002 and 0.001, respectively）. Linear regression analysis revealed that MPSI had a negative correlation with ALVEF and a positive correlation with ALVESV, ALVEDV （P=0.004, 0.008, and 0.016, respectively）. It was concluded that RT-MCE could accurately evaluate the left ventricular remodeling in patients with myocardial infarction after revascularization.

Dynamic Characteristic Mechanism of Atrial Septal Defect Using Real-Time Three-Dimensional Echocardiography and Evaluation of Right Ventricular Functions

The dynamic characteristics of the area of the atrial septal defect（ASD） were evaluated using the technique of real-time three-dimensional echocardiography（RT 3DE）, the potential factors responsible for the dynamic characteristics of the area of ASD were observed, and the overall and local volume and functions of the patients with ASD were measured. RT 3DE was performed on the 27 normal controls and 28 patients with ASD. Based on the three-dimensional data workstations, the area of ASD was measured at P wave vertex, R wave vertex, T wave starting point, and T wave terminal point and in the T-P section. The right atrial volume in the same time phase of the cardiac cycle and the motion displacement distance of the tricuspid annulus in the corresponding period were measured. The measured value of the area of ASD was analyzed. The changes in the right atrial volume and the motion displacement distance of the tricuspid annulus in the normal control group and the ASD group were compared. The right ventricular ejection fractions in the normal control group and the ASD group were compared using the RT 3DE long-axis eight-plane（LA 8-plane） method. Real-time three-dimensional volume imaging was performed in the normal control group and ASD group（n=30）. The right ventricular inflow tract, outflow tract, cardiac apex muscular trabecula dilatation, end-systolic volume, overall dilatation, end-systolic volume, and appropriate local and overall ejection fractions in both two groups were measured with the four-dimensional right ventricular quantitative analysis method（4D RVQ） and compared. The overall right ventricular volume and the ejection fraction measured by the LA 8-plane method and 4D RVQ were subjected to a related analysis. Dynamic changes occurred to the area of ASD in the cardiac cycle. The rules for dynamic changes in the area of ASD and the rules for changes in the right atrial volume in the cardiac cycle were consistent. The maximum value of the changes in the right atrial volume occurred in the end-systolic period when the peak of the curve appeared. The minimum value of the changes occurred in the end-systolic period and was located at the lowest point of the volume variation curve. The area variation curve for ASD and the motion variation curve for the tricuspid annulus in the cardiac cycle were the same. The displacement of the tricuspid annulus exhibited directionality. The measured values of the area of ASD at P wave vertex, R wave vertex, T wave starting point, T wave terminal point and in the T-P section were properly correlated with the right atrial volume（P〈0.001）. The area of ASD and the motion displacement distance of the tricuspid annulus were negatively correlated（P〈0.05）. The right atrial volumes in the ASD group in the cardiac cycle in various time phases increased significantly as compared with those in the normal control group（P=0.0001）. The motion displacement distance of the tricuspid annulus decreased significantly in the ASD group as compared with that in the normal control group（P=0.043）. The right ventricular ejection fraction in the ASD group was lower than that in the normal control group（P=0.032）. The ejection fraction of the cardiac apex trabecula of the ASD patients was significantly lower than the ejection fractions of the right ventricular outflow tract and inflow tract and overall ejection fraction. The difference was statistically significant（P=0.005）. The right ventricular local and overall dilatation and end-systolic volumes in the ASD group increased significantly as compared with those in the normal control group（P=0.031）. The a RVEF and the overall ejection fraction decreased in the ASD group as compared with those in the normal control group（P=0.0005）. The dynamic changes in the area of ASD and the motion curves for the right atrial volume and tricuspid annulus have the same dynamic characteristics. RT 3DE can be used to accurately evaluate the local and overall volume and functions of the right ventricle. The local and overall volume loads of the right ventricle in the ASD patients increase significantly as compared with those of the normal people. The right ventricular cardiac apex and the overall systolic function decrease.

Quantitative Analysis of Myocaridal Perfusion in Rabbits by Tansthoracic Real-time Myocardial Contrast Echocardiography

To evaluate the feasibility of real-time myocardial contrast echocardiography （RTMCE） by quantitative analysis of myocardial perfusion in rabbits, transthoracic RTMCE was performed in 10 healthy rabbits by using continuous infusion of SonoVue into the auricular vein. The short axis view at the papillary muscle level was obtained. The duration of the time that the contrast took to appear in right heart, left heart and myocardium was recorded. The regional myocardial signal intensity （SI） versus re-filling time plots were fitted to an exponential function： y（t） =A（1–e–β（t–t0）） ＋ C, where y is SI at any given time, A is the SI plateau that reflects myocardial blood volume, and β is the slope of the refilling curve that reflects myocardial microbubble velocity. The A, β and A×β values at different infusion rate of SonoVue were analyzed and the A, β and A×β values in each segment in the short axis view at the papillary muscle level were compared. All the animal experiments were successful and high-quality im-ages were obtained. The best intravenous infusion rate for SonoVue was 30 mL/h. The contrast appeared in right heart, left heart and myocardium at 7.5±2.2 s, 9.1±2.4 s and 12.2±1.6 s respectively. After 16.6±2.3s, myocardial opacification reached a steady state. The mean A, β and A×β value in the short axis view at the papillary muscle level were 9.8±3.0 dB, 1.4±0.5 s-1 and 13.5±3.6 dB×s-1 respectively. A, β and A×β values showed no significant differences among 6 segments. It was suggested that RTMCE was feasible for quantitative analysis of myocardial perfusion in rabbits. It provides a non-invasive method to evaluate the myocardial perfusion in rabbit disease models.

Evaluation of Biventricular Volume and Systolic Function in Children with Ventricular Septal Defect and Moderate to Severe Pulmonary Hypertension Using Real-Time Three-Dimensional Echocardiography

Background: Real-time three-dimensional echocardiography (RT-3DE) could obtain ventricular volume andejection fraction rapidly and non-invasively without relying on ventricular morphology. This study aims to useRT-3DE to evaluate the changes in biventricular volume and systolic function in children with ventricular septaldefect (VSD) and moderate to severe pulmonary hypertension (PH) before surgery. Methods: In this study18 children with VSD and moderate to severe PH (VSD + PH Group) and 18 healthy children of the sameage (Control Group) were recruited. Biventricular volume and systolic function were evaluated by RT-3DE.The measurements included: left and right ventricular volume indexed to body surface area (BSA), stroke volume(SV) indexed to BSA, and ejection fraction (EF). Results: The results showed left and right ventricular volumeindexed to BSA and SV indexed to BSA were significantly increased in VSD + PH Group (VSD + PH Groupvs. Control Group), LVEDV/BSA (ml/m2): 48.67 ± 21.46 vs. 25.59 ± 6.96, RVEDV/BSA (ml/m2): 55.98 ±15.35 vs. 27.69 ± 4.37, LVSV/BSA (ml/m2): 24.08 ± 9.30 vs. 15.14 ± 4.29, RVSV/BSA (ml/m2): 26.02 ± 8.87 vs.14.11 ± 2.89, (P < 0.05). While for EF in VSD + PH Group decreased (VSD + PH Group vs. Control Group),LVEF: 50.93 ± 7.50% vs. 59.38 ± 7.24%, RVEF: 45.84 ± 7.71% vs. 51.05 ± 6.90% (P < 0.05). Conclusion: Inchildren with VSD and moderate to severe PH, increased biventricular volume and decreased systolic functionwere observed with RT-3DE, but biventricular systolic function remained within acceptable limits. The childrenin this study recovered well after surgery without serious perioperative complications, suggesting that biventricularsystolic function may help facilitate the surgical decision-making process in children with VSD and moderate-toseverePH.

Evaluation of Myocardial Viability after Myocardial Infarction with Intravenous Real-time Myocardial Contrast Echocardiography

The myocardial viability after myocardial infarction was evaluated by intravenous myocardial contrast echocardiography. Intravenous real-time myocardial contrast echocardiography was performed on 18 patients with myocardial infarction before coronary revascularization. Follow-up echocardiography was performed 3 months after coronary revascularization. Segmental wall motion was assessed using 18-segment LV model and classified as normal, hypokinesis, akinesis and dyskinesis. Viable myocardium was defined by evident improvement of segmental wall motion 3 months after coronary revascularization. Myocardial perfusion was assessed by visual interpretation and divided into 3 conditions： homogeneous opacification; partial or reduced opaciflcation or subendocardial contrast defect; contrast defect. The former two conditions were used as the standard to define the viable myocardium. The results showed that 109 abnormal wall motion segments were detected among 18 patients with myocardial infarction, including 47 segments of hypokinesis, 56 segments of akinesis and 6 segments of dyskinesis. The wall motion of 2 segments with hypokinesis before coronary revascularization which showed homogeneous opacification, 14 of 24 segments with hypokinese and 20 of 24 segments with akinese before coronary revascularization which showed partial or reduced opaciflcation or subendocardial contrast defect was improved 3 months after coronary revascularization. In our study, the sensitivity and specificity of evaluation of myocardial viability after myocardial infarction by intravenous real-time myocardial contrast echocardiography were 94.7% and 78.9%, respectively. It was concluded that intravenous real-time myocardial contrast echocardiography could accurately evaluate myocardial viability after myocardial infarction.

Assessment of Left Atrial Function by Full Volume Real-time Three-dimensional Echocardiography and Left Atrial Tracking in Essential Hypertension Patients with Different Patterns of Left Ventricular Geometric Models

Objective To evaluate left atrial function in essential hypertension patients with different patterns of left ventricular geometric models by real-time three-dimensional echocardiography(RT-3DE)and left atrial tracking(LAT).Methods One hundred and thirty-three patients with essential hypertension were divided into four groups according to criteria proposed by Ganau et al:36 patients in normal pattern group(I),34 patients in concentric remodelling pattern group(II),33 patients in concentric hypertrophy pattern group(III),and 30patients in eccentric hypertrophy pattern group(IV).Thirty-two healthy volunteers were enrolled in this study.RT-3DE and LAT were used to obtain the volume-time and emptying fraction curves,and then the maximal volume,minimal volume,stroke volume,presystolic volume,ejection fraction,systolic filling rate,early diastolic emptying rate and late diastolic emptying rate of the left atrium were measured.Conduit volume and passive emptying volume of the left atrium were calculated.Results Left atrial indexes,conduit volume,passive emptying volume,and early diastolic emptying rate decreased,while the other indices increased in the group I compared with the control group(all P<0.05).Compared with the control group,I and II groups,the left atrial volume parameters manifested change in the group III and group IV(all P<0.01).Left atrial ejection fraction measured by RT-3DE or LAT,and late diastolic emptying rate were lower in the group IV compared with the group III(all P<0.05).There was no difference in left atrial conduit volume,passive emptying volume,and early diastolic left atrial emptying rate between the group II and group I(all P>0.05).There was a positive correlation between RT-3DE and LAT in evaluating left atrial function.Conclusions Left atrial booster pump function decreases in the eccentric hypertrophy pattern.Left atrial conduit function is unchanged in the normal pattern and the concentric remodelling pattern groups.RT-3DE and LAT technology can be used for quantitative evaluation of left atrial volume and function.

QUANTITATIVE ASSESSMENT OF MYOCARDIAL PERFUSION DEFECTS WITH REAL-TIME THREE-DIMENSIONAL MYOCARDIAL CONTRAST ECHOCARDIOGRAPHY

Objective To evaluate the feasibility and accuracy of measurement of myocardial perfusion defects with intravenous contrast-enhanced real-time three-dimensional echocardiography (CE-RT3DE). Methods RT3DE was performed in 21 open-chest mongrel dogs undergoing acute ligation of the left anterior descending artery (LAD, n=14) or distal branch of the left circumflex artery (LCX, n=7). A perfluorocarbon microbubble contrast agent was injected intravenously to assess the resulting myocardial perfusion defects with Philips Sonos-7500 ultrasound system. Evans blue dye was injected into the occluded coronary artery for subsequent anatomic identification of underperfused myocardium. In vitro anatomic measurement of myocardial mass after removal of the animal’s heart was regarded as the control. Blinded off-line calculation of left ventricular mass and perfusion defect mass from RT3DE images were performed using an interactive aided-manual tracing technique.Results Total left ventricular (LV) myocardial mass ranged from 38.9 to 78.5 (mean±SD: 60.0±10.1) g. The mass of perfusion defect ranged from 0 to 21.4 (mean±SD: 12.0±5.0) g or 0 to 27% of total LV mass (mean±SD: 19%±6%). The RT3DE estimation of total LV mass (mean±SD: 59.8±9.9 g) strongly correlated with the anatomic measurement (r=0.98; y=2.01+0.96x). The CE-RT3DE calculation of the mass of underperfused myocardium (mean±SD: 12.3±5.3 g) also strongly correlated with the anatomic measurement (r=0.96; y=-0.10+1.04x) and when expressed as percentage of total LV mass (r=0.95; y=-0.20+1.04x). Conclusions RT3DE with myocardial contrast opacification could accurately estimate underperfused myocardial mass in dogs of acute coronary occlusion and would play an important role in quantitative assessment of myocardial perfusion defects in patients with coronary artery disease.

An initial study on left ventricular diastolic function in patients with hypertrophy cardiomyopathy using single-beat, real-time, three-dimensional echocardiography

ObjectivesTo 由使用单个敲击的、即时、三维的 echocardiography (RT-3DE ) 与 hypertrophic 心肌症(HCM ) 在病人估计地区性的心脏舒张的功能 .MethodsSixty -- 有在和五十匹配年龄、匹配性的正常控制的湾穴节奏的 HCM 的五个病人被二维的 echocardiography (2DE ) 和 RT-3DE 学习。参数由包括的 RT-3DE 分析了：留给室( LV )体积，左室的喷射部分( LVEF )，结束心脏舒张的球状索引( EDSI )，心脏舒张的 dyssynchrony 索引( DDI )，分散结束扩张( DISPED )，并且由 RT-3DE 使 17 部分卷时间 curves.ResultsEvaluated 正常化， LVEF 与 2DE 相比是稍微更低的( 63.2 &#x000b1 ；6.8% 对 59.1 &#x000b1；6.4% ， P &#x0003c；0.0001 ) 。正常题目为所有 LV 片断有相对一致的容量的曲线。在 HCM 病人，部分容量的曲线是 dyssynchronous。在结束扩张的增加的 DDI 和 DISPED 与 HCM 在病人被观察(9.95 &#x000b1；3.75， 41.76 &#x000b1；17.19， P &#x0003c；0.0001 ) ，并且并非所有反常容量的片断与 HCM 发生在 hypertrophic regions.ConclusionsPatients 在扩张阶段，和这现出症状之前的潜的损害介绍了地区性的心脏舒张的 dyssynchrony 能被单个敲击的 RT-3DE 认出。

Real-Time Remote-Mentored Echocardiography in Management of Newborns with Critical Congenital Heart Defects

Background:The management of suspected critical congenital heart defects(CCHD)relies on timely echocardiographic diagnosis.The availability of experienced echocardiographers is limited or even non-existent in many hospitals with obstetric units.This study evaluates remote-mentored echocardiography performed by physicians without experience in imaging of congenital heart defects(CHD).Methods:The setup included a pediatric cardiologist in a separate room,guiding a physician without experience in echocardiographic imaging of CHD in the examination of a symptomatic newborn.This remote-mentoring pair was blinded to the diagnosis of the newborn and presented with a simplified patient history.The echocardiographic images were streamed to the laptop of the mentor,along with a webcam feed showing the probe position.The task was to identify CCHD in need of immediate transfer to a pediatric cardiac surgical center.The result was compared to the previously completed echocardiographic report and the clinical decision of the patient-responsible pediatric cardiologist.Results:During 17 months,15 newborns were recruited.All six newborns with CCHD were correctly labeled by the remotementoring pair.One newborn with Tetralogy of Fallot was erroneously labeled as needing immediate transfer.Eight newborns without CCHD were correctly labeled.Conclusions:Remote-mentored echocardiography performed by examiners without experience in imaging CHD identified all newborns with CCHD in need of immediate transfer for specialist care.The setup shows promising results for improving the management of CCHD in hospitals without continuous pediatric cardiology service.

Nanomaterial-assisted wearable glucose biosensors for noninvasive real-time monitoring:Pioneering point-of-care and beyond

This review explores glucose monitoring and management strategies,emphasizing the need for reliable and userfriendly wearable sensors that are the next generation of sensors for continuous glucose detection.In addition,examines key strategies for designing glucose sensors that are multi-functional,reliable,and cost-effective in a variety of contexts.The unique features of effective diabetes management technology are highlighted,with a focus on using nano/biosensor devices that can quickly and accurately detect glucose levels in the blood,improving patient treatment and control of potential diabetes-related infections.The potential of next-generation wearable and touch-sensitive nano biomedical sensor engineering designs for providing full control in assessing implantable,continuous glucose monitoring is also explored.The challenges of standardizing drug or insulin delivery doses,low-cost,real-time detection of increased blood sugar levels in diabetics,and early digital health awareness controls for the adverse effects of injectable medication are identified as unmet needs.Also,the market for biosensors is expected to expand significantly due to the rising need for portable diagnostic equipment and an ever-increasing diabetic population.The paper concludes by emphasizing the need for further research and development of glucose biosensors to meet the stringent requirements for sensitivity and specificity imposed by clinical diagnostics while being cost-effective,stable,and durable.

Integrated strategy for real-time wind power fluctuation mitigation and energy storage system control

To address the impact of wind-power fluctuations on the stability of power systems,we propose a comprehensive approach that integrates multiple strategies and methods to enhance the efficiency and reliability of a system.First,we employ a strategy that restricts long-and short-term power output deviations to smoothen wind power fluctuations in real time.Second,we adopt the sliding window instantaneous complete ensemble empirical mode decomposition with adaptive noise(SW-ICEEMDAN)strategy to achieve real-time decomposition of the energy storage power,facilitating internal power distribution within the hybrid energy storage system.Finally,we introduce a rule-based multi-fuzzy control strategy for the secondary adjustment of the initial power allocation commands for different energy storage components.Through simulation validation,we demonstrate that the proposed comprehensive control strategy can smoothen wind power fluctuations in real time and decompose energy storage power.Compared with traditional empirical mode decomposition(EMD),ensemble empirical mode decomposition(EEMD),and complete ensemble empirical mode decomposition with adaptive noise(CEEMDAN)decomposition strategies,the configuration of the energy storage system under the SW-ICEEMDAN control strategy is more optimal.Additionally,the state-of-charge of energy storage components fluctuates within a reasonable range,enhancing the stability of the power system and ensuring the secure operation of the energy storage system.

Models to Simulate Effective Coverage of Fire Station Based on Real-Time Travel Times

In recent years,frequent fire disasters have led to enormous damage in China.Effective firefighting rescues can minimize the losses caused by fires.During the rescue processes,the travel time of fire trucks can be severely affected by traffic conditions,changing the effective coverage of fire stations.However,it is still challenging to determine the effective coverage of fire stations considering dynamic traffic conditions.This paper addresses this issue by combining the traveling time calculationmodelwith the effective coverage simulationmodel.In addition,it proposes a new index of total effective coverage area(TECA)based on the time-weighted average of the effective coverage area(ECA)to evaluate the urban fire services.It also selects China as the case study to validate the feasibility of the models,a fire station(FS-JX)in Changsha.FS-JX station and its surrounding 9,117 fire risk points are selected as the fire service supply and demand points,respectively.A total of 196 simulation scenarios throughout a consecutiveweek are analyzed.Eventually,1,933,815 sets of valid sample data are obtained.The results showed that the TECA of FS-JX is 3.27 km^(2),which is far below the standard requirement of 7.00 km^(2) due to the traffic conditions.The visualization results showed that three rivers around FS-JX interrupt the continuity of its effective coverage.The proposed method can provide data support to optimize the locations of fire stations by accurately and dynamically determining the effective coverage of fire stations.

A deep reinforcement learning approach to gasoline blending real-time optimization under uncertainty

The gasoline inline blending process has widely used real-time optimization techniques to achieve optimization objectives,such as minimizing the cost of production.However,the effectiveness of real-time optimization in gasoline blending relies on accurate blending models and is challenged by stochastic disturbances.Thus,we propose a real-time optimization algorithm based on the soft actor-critic(SAC)deep reinforcement learning strategy to optimize gasoline blending without relying on a single blending model and to be robust against disturbances.Our approach constructs the environment using nonlinear blending models and feedstocks with disturbances.The algorithm incorporates the Lagrange multiplier and path constraints in reward design to manage sparse product constraints.Carefully abstracted states facilitate algorithm convergence,and the normalized action vector in each optimization period allows the agent to generalize to some extent across different target production scenarios.Through these well-designed components,the algorithm based on the SAC outperforms real-time optimization methods based on either nonlinear or linear programming.It even demonstrates comparable performance with the time-horizon based real-time optimization method,which requires knowledge of uncertainty models,confirming its capability to handle uncertainty without accurate models.Our simulation illustrates a promising approach to free real-time optimization of the gasoline blending process from uncertainty models that are difficult to acquire in practice.

Phase behavior of gas condensate in porous media using real-time computed tomography scanning

The phase behavior of gas condensate in reservoir formations differs from that in pressure-volume-temperature(PVT)cells because it is influenced by porous media in the reservoir formations.Sandstone was used as a sample to investigate the influence of porous media on the phase behavior of the gas condensate.The pore structure was first analyzed using computed tomography(CT)scanning,digital core technology,and a pore network model.The sandstone core sample was then saturated with gas condensate for the pressure depletion experiment.After each pressure-depletion state was stable,realtime CT scanning was performed on the sample.The scanning results of the sample were reconstructed into three-dimensional grayscale images,and the gas condensate and condensate liquid were segmented based on gray value discrepancy to dynamically characterize the phase behavior of the gas condensate in porous media.Pore network models of the condensate liquid ganglia under different pressures were built to calculate the characteristic parameters,including the average radius,coordination number,and tortuosity,and to analyze the changing mechanism caused by the phase behavior change of the gas condensate.Four types of condensate liquid(clustered,branched,membranous,and droplet ganglia)were then classified by shape factor and Euler number to investigate their morphological changes dynamically and elaborately.The results show that the dew point pressure of the gas condensate in porous media is 12.7 MPa,which is 0.7 MPa higher than 12.0 MPa in PVT cells.The average radius,volume,and coordination number of the condensate liquid ganglia increased when the system pressure was between the dew point pressure(12.7 MPa)and the pressure for the maximum liquid dropout,Pmax(10.0 MPa),and decreased when it was below Pmax.The volume proportion of clustered ganglia was the highest,followed by branched,membranous,and droplet ganglia.This study provides crucial experimental evidence for the phase behavior changing process of gas condensate in porous media during the depletion production of gas condensate reservoirs.

A Real-time Lithological Identification Method based on SMOTE-Tomek and ICSA Optimization

In petroleum engineering,real-time lithology identification is very important for reservoir evaluation,drilling decisions and petroleum geological exploration.A lithology identification method while drilling based on machine learning and mud logging data is studied in this paper.This method can effectively utilize downhole parameters collected in real-time during drilling,to identify lithology in real-time and provide a reference for optimization of drilling parameters.Given the imbalance of lithology samples,the synthetic minority over-sampling technique(SMOTE)and Tomek link were used to balance the sample number of five lithologies.Meanwhile,this paper introduces Tent map,random opposition-based learning and dynamic perceived probability to the original crow search algorithm(CSA),and establishes an improved crow search algorithm(ICSA).In this paper,ICSA is used to optimize the hyperparameter combination of random forest(RF),extremely random trees(ET),extreme gradient boosting(XGB),and light gradient boosting machine(LGBM)models.In addition,this study combines the recognition advantages of the four models.The accuracy of lithology identification by the weighted average probability model reaches 0.877.The study of this paper realizes high-precision real-time lithology identification method,which can provide lithology reference for the drilling process.

Pore-pressure and stress-coupled creep behavior in deep coal:Insights from real-time NMR analysis

Understanding the variations in microscopic pore-fracture structures(MPFS) during coal creep under pore pressure and stress coupling is crucial for coal mining and effective gas treatment. In this manuscript, a triaxial creep test on deep coal at various pore pressures using a test system that combines in-situ mechanical loading with real-time nuclear magnetic resonance(NMR) detection was conducted.Full-scale quantitative characterization, online real-time detection, and visualization of MPFS during coal creep influenced by pore pressure and stress coupling were performed using NMR and NMR imaging(NMRI) techniques. The results revealed that seepage pores and microfractures(SPM) undergo the most significant changes during coal creep, with creep failure gradually expanding from dense primary pore fractures. Pore pressure presence promotes MPFS development primarily by inhibiting SPM compression and encouraging adsorption pores(AP) to evolve into SPM. Coal enters the accelerated creep stage earlier at lower stress levels, resulting in more pronounced creep deformation. The connection between the micro and macro values was established, demonstrating that increased porosity at different pore pressures leads to a negative exponential decay of the viscosity coefficient. The Newton dashpot in the ideal viscoplastic body and the Burgers model was improved using NMR experimental results, and a creep model that considers pore pressure and stress coupling using variable-order fractional operators was developed. The model’s reasonableness was confirmed using creep experimental data. The damagestate adjustment factors ω and β were identified through a parameter sensitivity analysis to characterize the effect of pore pressure and stress coupling on the creep damage characteristics(size and degree of difficulty) of coal.