المؤلفون: Abdelghani, Leghouchi

المصدر: World Journal of Engineering, 2023, Vol. 21, Issue 2, pp. 376-385.

الوصول الحر: http://www.emeraldinsight.com/doi/10.1108/WJE-10-2022-0405Test

المؤلفون: Zhang, Wenyang, Crempien, Jorge GF, Kurtulus, Asli, Chen, Peng‐Yu, Arduino, Pedro, Taciroglu, Ertugrul

المصدر: Earthquake Engineering & Structural Dynamics. 52(4)

مصطلحات موضوعية: Civil Engineering, Engineering, earthquake wave propagation, high frequency, physics-based ground motion simulation, regional-scale analysis, Humans, Tuberculosis, Ureteral Neoplasms, Contrast Media, Diagnosis, Differential, Retrospective Studies, Female, Contrast-enhanced ultrasound, malignant tumour, tuberculous, ureter, Public Health and Health Services, Epidemiology, Veterinary sciences, Clinical sciences

الوصف: This study aimed to evaluate the contrast-enhanced ultrasound (CEUS) features of ureteral tuberculosis (UTB) and ureteral malignant tumour and to explore its application value in the differentiation of UTB from ureteral tumour. The ultrasound (US) and CEUS imaging features of 33 and 12 cases of pathologically confirmed UTB and ureteral malignant tumour, respectively, were retrospectively evaluated, and echo of the ureteral wall, abnormal echo of the lumen, degree of ureteral dilation and CEUS patterns of the two diseases were statistically analysed. The results revealed that the lumen echo of UTB was hyperechoic or anechoic, whereas that of ureteral tumour lesions was hypoechoic (χ2 = 28.22, P < 0.001). The wall echo of the obstruction site differed between the two diseases; in UTB, the ureteral wall was thickened but the outer wall remained intact, whereas in ureteral tumour, both the malignant tumour wall and outer wall were irregular (χ2 = 30.25, P < 0.001). CEUS of UTB revealed nonenhancement or heterogeneous enhancement in the lumen, whereas that of ureteral tumours revealed significant homogeneous enhancement (χ2 = 30.25, P < 0.001). Thus, CEUS can reveal lesion microcirculation and be used to evaluate blood supply characteristics in the lesion, indicating that it has high potential for differentiating the two diseases.

وصف الملف: application/pdf

الوصول الحر: https://escholarship.org/uc/item/3p1538hmTest

المؤلفون: Milašinović, Dragan D.

المصدر: Engineering Computations, 2023, Vol. 40, Issue 9/10, pp. 2615-2647.

الوصول الحر: http://www.emeraldinsight.com/doi/10.1108/EC-08-2022-0574Test

المؤلفون: Csernyava, Oliver, Pavo, Jozsef, Badics, Zsolt

المصدر: COMPEL -The international journal for computation and mathematics in electrical and electronic engineering, 2023, Vol. 42, Issue 5, pp. 1212-1224.

الوصول الحر: http://www.emeraldinsight.com/doi/10.1108/COMPEL-01-2023-0024Test

المؤلفون: Bartolo, Michelle A, Qureshi, M Umar, Colebank, Mitchel J, Chesler, Naomi C, Olufsen, Mette S

المصدر: Biomechanics and Modeling in Mechanobiology. 21(1)

مصطلحات موضوعية: Fluid Mechanics and Thermal Engineering, Engineering, Biomedical Engineering, Lung, Cardiovascular, Heart Disease, Bioengineering, Aetiology, 2.1 Biological and endogenous factors, Blood Pressure, Heart Failure, Hemodynamics, Humans, Hypertension, Pulmonary, Pulmonary Artery, Pulmonary hypertension, Micro-circulation, Wall shear stress, Cyclic stretch, Left heart disease, Computational modeling, Pulse wave propagation, Mechanical Engineering, Biomedical engineering

الوصف: Isolated post-capillary pulmonary hypertension (Ipc-PH) occurs due to left heart failure, which contributes to 1 out of every 9 deaths in the United States. In some patients, through unknown mechanisms, Ipc-PH transitions to combined pre-/post-capillary PH (Cpc-PH) and is associated with a dramatic increase in mortality. Altered mechanical forces and subsequent biological signaling in the pulmonary vascular bed likely contribute to the transition from Ipc-PH to Cpc-PH. However, even in a healthy pulmonary circulation, the mechanical forces in the smallest vessels (the arterioles, capillary bed, and venules) have not been quantitatively defined. This study is the first to examine this question via a computational fluid dynamics model of the human pulmonary arteries, arterioles, venules, and veins. Using this model, we predict temporal and spatial dynamics of cyclic stretch and wall shear stress with healthy and diseased hemodynamics. In the normotensive case for large vessels, numerical simulations show that large arteries have higher pressure and flow than large veins, as well as more pronounced changes in area throughout the cardiac cycle. In the microvasculature, shear stress increases and cyclic stretch decreases as vessel radius decreases. When we impose an increase in left atrial pressure to simulate Ipc-PH, shear stress decreases and cyclic stretch increases as compared to the healthy case. Overall, this model predicts pressure, flow, shear stress, and cyclic stretch that providing a way to analyze and investigate hypotheses related to disease progression in the pulmonary circulation.

وصف الملف: application/pdf

الوصول الحر: https://escholarship.org/uc/item/1xn954cpTest

المؤلفون: Schiemer, Melanie, Reum, Thomas, Toepfer, Hannes

المصدر: COMPEL -The international journal for computation and mathematics in electrical and electronic engineering, 2023, Vol. 42, Issue 3, pp. 776-786.

الوصول الحر: http://www.emeraldinsight.com/doi/10.1108/COMPEL-09-2022-0313Test

المؤلفون: Anne Etiko

مصطلحات موضوعية: Representation and Critique of DIKW Hierarchy, Management Science and Operations Research, Decision Sciences, Social Sciences, Study of Earthquake Precursor Phenomena, Geophysics, FOS Earth and related environmental sciences, Earth and Planetary Sciences, Physical Sciences, Rock Mechanics and Wave Propagation in Geomedia, Mechanics of Materials, Engineering, Mining Induced Seismicity, Resilience materials science, Critical infrastructure, Urbanization, Vulnerability computing, Environmental planning, Green infrastructure, Urban planning, Desk, Environmental resource management, Civil engineering, FOS Civil engineering, Computer science, Geography, Environmental science, Computer security, Physics, Economics

الوصف: Purpose: The main objective of this study was to explore urban geology and infrastructure resilience. Methodology: The study adopted a desktop research methodology. Desk research refers to secondary data or that which can be collected without fieldwork. Desk research is basically involved in collecting data from existing resources hence it is often considered a low cost technique as compared to field research, as the main cost is involved in executive's time, telephone charges and directories. Thus, the study relied on already published studies, reports and statistics. This secondary data was easily accessed through the online journals and library. Findings: The findings revealed that there exists a contextual and methodological gap relating to urban geology and infrastructure resilience. Preliminary empirical review revealed that urban geology and infrastructure resilience is essential in the face of rapid urbanization and increasing geological hazards. It emphasizes the vulnerability of urban ... : الغرض: كان الهدف الرئيسي من هذه الدراسة هو استكشاف الجيولوجيا الحضرية ومرونة البنية التحتية. المنهجية: اعتمدت الدراسة منهجية البحث المكتبي. يشير البحث المكتبي إلى البيانات الثانوية أو تلك التي يمكن جمعها دون العمل الميداني. يشارك البحث المكتبي بشكل أساسي في جمع البيانات من الموارد الحالية، وبالتالي غالبًا ما يُنظر إليه على أنه تقنية منخفضة التكلفة مقارنة بالبحث الميداني، حيث يتم تضمين التكلفة الرئيسية في وقت المسؤول التنفيذي ورسوم الهاتف والأدلة. وبالتالي، اعتمدت الدراسة على الدراسات والتقارير والإحصاءات المنشورة بالفعل. تم الوصول إلى هذه البيانات الثانوية بسهولة من خلال المجلات والمكتبة عبر الإنترنت. النتائج: كشفت النتائج عن وجود فجوة سياقية ومنهجية تتعلق بالجيولوجيا الحضرية ومرونة البنية التحتية. كشفت المراجعة التجريبية الأولية أن الجيولوجيا الحضرية ومرونة البنية التحتية ضرورية في مواجهة التحضر السريع والمخاطر الجيولوجية المتزايدة. ويؤكد على ضعف البنية التحتية الحضرية أمام المخاطر الجيولوجية، مثل الزلازل والانهيارات الأرضية، ويسلط الضوء على الحاجة إلى تحسين قوانين البناء وممارسات البناء وتصميم البنية ...

العلاقة: https://dx.doi.org/10.60692/6te8c-v6150Test

الإتاحة: https://doi.org/10.60692/xrkhn-r7b7210.60692/6te8c-v6150Test

المؤلفون: Mikhaltsevitch, Vassily, Lebedev, Maxim

المصدر: Research outputs 2022 to 2026

مصطلحات موضوعية: elastic properties, seismic frequency, strain gauges, wave propagation, Civil and Environmental Engineering, Engineering, Geotechnical Engineering

الوصف: Numerous experimental and theoretical studies undertaken to determine the effective stress coefficient for seismic velocities in rocks stem from the importance of this geomechanical parameter both for monitoring changes in rock saturation and pore pressure distribution in connection with reservoir production, and for overpressure prediction in reservoirs and formations from seismic data. The present work pursues a task to determine, in the framework of a low-frequency laboratory study, the dependence of the elastic moduli of n-decane-saturated sandstone on the relationship between pore and confining pressures. The study was conducted on a sandstone sample with high quartz and notable clay content in a quasi-static regime when a 100 mL tank filled with n-decane was directly connected to the pore space of the sample. The measurements were carried out at a seismic frequency of 2 Hz and strains, controlled by semiconductor strain gauges, not exceeding 10−6. The study was performed using a forced-oscillation laboratory apparatus utilizing the stress–strain relationship. The dynamic elastic moduli were measured in two sets of experiments: at constant pore pressures of 0, 1, and 5 MPa and differential pressure (defined as a difference between confining and pore pressures) that varied from 3 to 19 MPa; and at a constant confining pressure of 20 MPa and pore pressure that varied from 1 to 17 MP. It was shown that the elastic moduli obtained in the measurements were in good agreement with the Gassmann moduli calculated for the range of differential pressures used in our experiments, which corresponds to the effective stress coefficient equal to unity.

وصف الملف: application/pdf

العلاقة: https://ro.ecu.edu.au/ecuworks2022-2026/3847Test; https://ro.ecu.edu.au/context/ecuworks2022-2026/article/4848/viewcontent/Measurements_20of_20the_20effective_20stress_20coefficient_20for_20elastic.pdfTest

الإتاحة: https://doi.org/10.3390/s24041122Test
https://ro.ecu.edu.au/ecuworks2022-2026/3847Test
https://ro.ecu.edu.au/context/ecuworks2022-2026/article/4848/viewcontent/Measurements_20of_20the_20effective_20stress_20coefficient_20for_20elastic.pdfTest

المؤلفون: Hubbard, Peter G, Vantassel, Joseph P, Cox, Brady R, Rector, James W, Yust, Michael BS, Soga, Kenichi

المصدر: Sensors. 22(12)

مصطلحات موضوعية: Engineering, Electrical Engineering, Electronics, Sensors and Digital Hardware, Bioengineering, DAS, geophones, transfer function, wave propagation, strain measurement, DFOS, Analytical Chemistry, Environmental Science and Management, Ecology, Distributed Computing, Electrical and Electronic Engineering, Electrical engineering, Electronics, sensors and digital hardware, Environmental management, Distributed computing and systems software

الوصف: Quantitative dynamic strain measurements of the ground would be useful for engineering scale problems such as monitoring for natural hazards, soil-structure interaction studies, and non-invasive site investigation using full waveform inversion (FWI). Distributed acoustic sensing (DAS), a promising technology for these purposes, needs to be better understood in terms of its directional sensitivity, spatial position, and amplitude for application to engineering-scale problems. This study investigates whether the physical measurements made using DAS are consistent with the theoretical transfer function, reception patterns, and experimental measurements of ground strain made by geophones. Results show that DAS and geophone measurements are consistent in both phase and amplitude for broadband (10 s of Hz), high amplitude (10 s of microstrain), and complex wavefields originating from different positions around the array when: (1) the DAS channels and geophone locations are properly aligned, (2) the DAS cable provides good deformation coupling to the internal optical fiber, (3) the cable is coupled to the ground through direct burial and compaction, and (4) laser frequency drift is mitigated in the DAS measurements. The transfer function of DAS arrays is presented considering the gauge length, pulse shape, and cable design. The theoretical relationship between DAS-measured and pointwise strain for vertical and horizontal active sources is introduced using 3D elastic finite-difference simulations. The implications of using DAS strain measurements are discussed including directionality and magnitude differences between the actual and DAS-measured strain fields. Estimating measurement quality based on the wavelength-to-gauge length ratio for field data is demonstrated. A method for spatially aligning the DAS channels with the geophone locations at tolerances less than the spatial resolution of a DAS system is proposed.

وصف الملف: application/pdf

الوصول الحر: https://escholarship.org/uc/item/1vr4134zTest

المؤلفون: Wang, Fangbo, Wang, Hexiang, Yang, Han, Feng, Yuan, Jeremić, Boris

مصطلحات موضوعية: Civil Engineering, Engineering, Stochastic seismic wave propagation, Modular methodology, Domain reduction method, Intrusive Galerkin stochastic finite element, method, Hermite polynomial chaos, Resources Engineering and Extractive Metallurgy, Interdisciplinary Engineering, Geological & Geomatics Engineering, Civil engineering, Resources engineering and extractive metallurgy

الوصف: Presented here is a modular methodology for time-domain stochastic seismic wave propagation analysis. Presented methodology is designed to analyse uncertain seismic motions as an input, propagating through uncertain material. Traditional approach for uncertain wave propagation relies on models that include deep bedrock, local soil site, and their random process and random field information. Such models can become quite large and computationally intractable. The modular approach proposed herein features two step approach that allows separate consideration of the deep bedrock and local site along with corresponding random field information. The first step considers an auxiliary stochastic motions problem in the bedrock. Stochastic local site response can then be simulated in a reduced domain within certain depth from the surface. Application of uncertain seismic motions at depth, for local uncertain site response is done using stochastic effective forces developed through the Domain Reduction Method. By using Hermite polynomial chaos expansion to represent the non-Gaussian random field of material parameters and non-stationary random process of seismic motion, the proposed modular methodology is formulated using intrusive stochastic Galerkin approach, as seen in the Stochastic Elastic–Plastic Finite Element Method (SEPFEM). Developed modular methodology is illustrated using a 1-D stochastic seismic wave propagation analysis with three cases, and simulation results are also verified with results from conventional approach.

وصف الملف: application/pdf

الوصول الحر: https://escholarship.org/uc/item/4ds1k84cTest