Статті в журналах: "Sbfet"

1

Gravenkamp, Hauke, Albert A. Saputra, and Sascha Eisenträger. "Three-dimensional image-based modeling by combining SBFEM and transfinite element shape functions." Computational Mechanics 66, no. 4 (August 4, 2020): 911–30. http://dx.doi.org/10.1007/s00466-020-01884-4.

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Abstract The scaled boundary finite element method (SBFEM) has recently been employed as an efficient tool to model three-dimensional structures, in particular when the geometry is provided as a voxel-based image. To this end, an octree decomposition of the computational domain is deployed, and each cubic cell is treated as an SBFE subdomain. The surfaces of each subdomain are discretized in the finite element sense. We improve on this idea by combining the semi-analytical concept of the SBFEM with a particular class of transition elements on the subdomains’ surfaces. Thus, a triangulation of these surfaces as executed in previous works is avoided, and consequently, the number of surface elements and degrees of freedom is reduced. In addition, these discretizations allow coupling elements of arbitrary order such that local p-refinement can be achieved straightforwardly.

2

LI, SHANGMING. "SCALED BOUNDARY FINITE ELEMENT METHOD FOR SEMI-INFINITE RESERVOIR WITH UNIFORM CROSS SECTION." International Journal of Computational Methods 09, no. 01 (March 2012): 1240006. http://dx.doi.org/10.1142/s0219876212400063.

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A unified scaled boundary finite element method (SBFEM) in the frequency domain was proposed for a semi-infinite reservoir with uniform cross section subjected to horizontal and vertical ground excitations, and a methodology was presented to solve the unified SBFEM through decomposing the unified SBFEM into two parts; one part modeling the reservoir subjected to horizontal excitations and the other part modeling the whole reservoir subjected to vertical excitations. The accuracy of the unified SBFEM and its solving methodology was validated through analyzing numerical examples. The SBFEM solutions were in good agreement with analytical or other numerical method's solutions.

3

Li, Shang Ming. "Transient Analysis of Dam-Reservoir Interaction Based on Dynamic Stiffness of SBFEM." Advanced Materials Research 378-379 (October 2011): 213–17. http://dx.doi.org/10.4028/www.scientific.net/amr.378-379.213.

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The scaled boundary finite element method (SBFEM) was extended to solve dam-reservoir interaction problems in the time domain and a dynamic stiffness used in the SBFEM of semi-infinite reservoir in the time domain was proposed, which was evaluated by the Bessel function. Based on the dynamic stiffness, transient responses subjected to horizontal ground motions were analyzed through coupling the SBFEM and finite element method (FEM). A dam was modeled by FEM, while the whole fluid in reservoir was modeled by the SBFEM alone or a combination of FEM and SBFEM. Two benchmark examples were considered to check the accuracy of the dynamic stiffness. Results were compared with those from analytical or substructure methods and good agreements were found.

4

Leshem, Eyal. "Antibiotics for travelers' diarrhea in children?: To SBET or not to SBET?" Travel Medicine and Infectious Disease 34 (March 2020): 101681. http://dx.doi.org/10.1016/j.tmaid.2020.101681.

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5

Galardi, Nicholas, Jay Collins, and Kara Friend. "Use of Early Gastrografin Small Bowel Follow-through in Small Bowel Obstruction Management." American Surgeon 79, no. 8 (August 2013): 794–96. http://dx.doi.org/10.1177/000313481307900820.

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Small bowel follow-through (SBFT) is a diagnostic tool commonly used in the management of patients with small bowel obstruction (SBO). This study assessed whether early implementation of Gastrografin SBFT would reduce the time to resolution of the SBO and decrease the time to operative intervention. In this retrospective chart review, 103 patients with the clinical diagnosis of adhesive SBO were evaluated. End points of the study were resolution of SBO with non-operative management or operative intervention. The patient group that had received a SBFT was then compared with those that did not receive a SBFT. There were 103 patients with adhesive SBO who met inclusion criteria for this study. Seventy-two of 103 patients had undergone Gastrografin SBFT and 31 did not. In the SBFT group, mean time to the operating room was 1.0 days after SBFTs, whereas in the group that did not receive SBFT, it was 3.7 days ( P < 0.0001). Mean time to nonoperative resolution of SBO in the SBFT group was 1.8 days and 4.7 days in the no SBFT group ( P < 0.0001). There were no Gastrografin-related complications. Obtaining Gastrografin SBFT in patients with adhesive SBO leads to both a shorter time in identifying the need for operative intervention and to resolution of SBO with nonoperative management. SBFT seems to be a more definitive assessment of whether an SBO will resolve on its own or if operative intervention is necessary.

6

LI, MIAO, YONG ZHANG, HONG ZHANG, and HONG GUAN. "NUMERICAL STABILITY AND ACCURACY OF THE SCALED BOUNDARY FINITE ELEMENT METHOD IN ENGINEERING APPLICATIONS." ANZIAM Journal 57, no. 2 (October 2015): 114–37. http://dx.doi.org/10.1017/s1446181115000255.

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The scaled boundary finite element method (SBFEM) is a semi-analytical computational method initially developed in the 1990s. It has been widely applied in the fields of solid mechanics, oceanic, geotechnical, hydraulic, electromagnetic and acoustic engineering problems. Most of the published work on SBFEM has focused on its theoretical development and practical applications, but, so far, no explicit discussion on the numerical stability and accuracy of its solution has been systematically documented. However, for a reliable engineering application, the inherent numerical problems associated with SBFEM solution procedures require thorough analysis in terms of its causes and the corresponding remedies. This study investigates the numerical performance of SBFEM with respect to matrix manipulation techniques and their properties. Some illustrative examples are given to identify reasons for possible numerical difficulties, and corresponding solution schemes are proposed to overcome these problems.

7

Liu, Jun Yu, Feng Lin Xu, Bao Kuan Ning, and He Fan. "Evaluation of the T-Stress and the Higher Order Terms of the Elastic Crack Based on the SBFEM." Advanced Materials Research 838-841 (November 2013): 2275–78. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.2275.

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The Scaled Boundary Finite Element Method (abbr. SBFEM) developed by Wolf and Song is a numerical method which has a half analytical nature. In the paper, the asymptotic fields of central crack tip and single edge crack tip of the plane elastic plates are evaluated based on the SBFEM. Numerical examples are provided to demonstrate its high accuracy and effectiveness, and the numerical results show that SBFEM can calculate the SIFs, T-stress and the coefficients of higher order terms with higher efficiency and accuracy. The singular fields of crack-tip with complex configuration can be evaluated combining the sub-structuring technique (or super-element).

8

Daniel Junga, Jonathan, and Wilfried Beckerb. "An SBFEM Element for Thin-Walled Beams." International Journal of Aerospace and Lightweight Structures (IJALS) 3, no. 2 (2013): 207. http://dx.doi.org/10.3850/s2010428613000615.

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9

Liu, Jun Yu, Ping Zhang, Meng Han Liao, and Bao Kuan Ning. "Evaluation of the SIF for the Multiple Crack Problems." Applied Mechanics and Materials 638-640 (September 2014): 66–70. http://dx.doi.org/10.4028/www.scientific.net/amm.638-640.66.

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In elastic fracture mechanics the evaluation of the stress intensity factor (SIF) for multiple cracks problems is an important issue. In the paper the scaled boundary finite element method (SBFEM) is used to solve the SIF of mode I of multiple crack problems. The solving domain is partitioned into several sub-domains according to the number of cracks. Every sub-domain has its own scaling center. The characteristics of the SBFEM are preserved in every sub-domain. Numerical examples show that the SBFEM is effective with high accuracy in evaluating the multiple cracks fracture problems. It can be applied to treat the anisotropic materials conveniently. The stress intensity factors of unequal double-edged cracks in orthotropic material are provided.

10

Xu, Feng Lin, Jun Yu Liu, Bao Kuan Ning, and He Fan. "Evaluation of the Higher Order Terms of the Wedge-Splitting Specimen Based on the SBFEM." Applied Mechanics and Materials 477-478 (December 2013): 25–29. http://dx.doi.org/10.4028/www.scientific.net/amm.477-478.25.

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The scaled boundary finite element method (abbr. SBFEM) is a semi-analytical method developed by Wolf and Song. The analytical advantage of the solution in the radial direction allows SBFEM converge to the Williams expansion. The coefficients of the Williams expansion, including the stress intensity factor, the T-stress, and higher order terms can be calculated directly without further processing. In the paper the coefficients of higher order terms of the crack tip asymptotic field of typical wedge splitting specimens with two different loading arrangements are evaluated using SBFEM. Numerical results show the method has high accuracy and effectiveness. The results have certain significance on determining crack stability of the wedge-splitting specimen.

11

Brehm, Thomas, Christof Vinnemeier, and Thierry Rolling. "Notfallmäßige Selbstbehandlung für Reisende in Malariagebiete mit geringem Transmissionsrisiko." Flugmedizin · Tropenmedizin · Reisemedizin - FTR 24, no. 05 (October 2017): 227–29. http://dx.doi.org/10.1055/s-0043-118953.

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ZusammenfassungLeitlinien in mehreren europäischen Ländern empfehlen die notfallmäßige Selbstbehandlung einer Malaria (SBET) für Reisende in Malariagebiete mit geringem Transmissionsrisiko. Dabei sollen die mitgeführten Medikamente eingenommen werden, falls eine Malaria möglich und sofortige medizinische Hilfe nicht verfügbar ist. Über die Praktikabilität der SBET wurde innerhalb der Reisemedizin in der Vergangenheit vermehrt spekuliert. Neuere Daten stellen das Konzept der SBET für alle in Regionen mit niedrigem oder mittlerem Transmissionsrisiko Reisende infrage.

12

Licata, Andrew, Ismail El Moudden, Nicholas Bandy, Molly Sternick, and Rebecca Britt. "Diatrizoate (Gastrograffin®) Small Bowel Follow Through for Small Bowel Obstructions: Timing and Outcomes." American Surgeon 88, no. 4 (November 3, 2021): 722–27. http://dx.doi.org/10.1177/00031348211050823.

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Introduction The advent of the Gastrograffin® small bowel follow through (G-SBFT) has resulted in a decreased rate of operative intervention of small bowel obstructions (SBO); however, there is no data to suggest when G-SBFT should be performed. Methods We retrospectively reviewed 548 patients, admitted to 1 of 9 hospitals with a diagnosis of SBO. Patients were divided into two categories with regards to timing of G-SBFT: before (early) or after (late) 48 hours from admission. Primary outcomes were length of stay (LOS) and total cost. Secondary outcomes were operative interventions and mortality. Results Of the reviewed patients, 71% had the G-SBFT ordered early. Comparing early versus late, there were no differences in patient characteristics with regards to age, sex, or BMI. There was a significant difference between LOS (4 vs 8 days, P < 0.05) and total cost ($17,056.19 vs $33,292.00, P < 0.05). There was no difference in mortality (1.3% vs 2.6%, P = 0.239) or 30-day readmission rates (15.6% vs 15.9%, P = 0.509). Patients in the early group underwent fewer operations (20.7% vs 31.9%, P = 0.05). Discussion Patients that had a G-SBFT ordered early had a decreased LOS, total cost, and operative intervention. This suggests there is a benefit to ordering G-SBFT earlier in the hospital stay to reduce the overall disease burden, and that it is safe to do so with regards to mortality and readmissions. We therefore recommend ordering a G-SBFT within 48 hours to reduce LOS, cost, and need for an operation

13

Taves, Donald H., and Linda Probyn. "Cecal Carcinoma: Initially Diagnosed as Crohn's Disease on Small Bowel Follow-Through." Canadian Journal of Gastroenterology 15, no. 5 (2001): 337–40. http://dx.doi.org/10.1155/2001/212313.

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Lesions in the terminal ileum are often difficult to visualize on routine small bowel follow-through (SBFT) and may require further investigation to rule out associated abnormalities in the ileocecal valve or cecum. This may be done by peroral pneumocolon at the same sitting as the SBFT, but may require bowel preparation. Two cases of cecal carcinoma that were initially diagnosed as Crohn's disease on SBFT without further investigation of the cecum are reported.

14

Marcos, Celia, Alaa Adawy, and Irene Rodríguez. "Relationship between Textural Parameters of Lamellar Products Obtained by Acid Activation of Pure and Commercial Vermiculites and Their Iron and Water Content." Minerals 10, no. 8 (July 26, 2020): 661. http://dx.doi.org/10.3390/min10080661.

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The relationship between textural parameters (specific superficial area (SBET) and porosity (Vp)) of lamellar products obtained from HNO3-activated vermiculites and their iron and water content has been established. Two commercial vermiculites, one thermoexfoliated commercial vermiculite, and one pure vermiculite were nitric-acid-treated at 4 and 8 M concentrations for 1, 3, and 7 days. Untreated and treated samples were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and N2 physisorption analysis. The untreated vermiculites showed a direct relationship between their iron content and the values of SBET, Vp, and pore size; an inverse relationship was observed in the case of the treated samples. The iron content may prevent further leaching of cations but not water loss, therefore forming lamellar products with lower SBET and Vp values. The SBET and Vp values of the studied thermoexfoliated sample were higher than those of the starting sample. The SBET and Vp values of the activated thermoexfoliated sample were lower than those of the activated non-thermoexfoliated sample.

15

LI, FENGZHI, and QIANG TU. "THE SCALED BOUNDARY FINITE ELEMENT ANALYSIS OF SEEPAGE PROBLEMS IN MULTI-MATERIAL REGIONS." International Journal of Computational Methods 09, no. 01 (March 2012): 1240008. http://dx.doi.org/10.1142/s0219876212400087.

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The scaled boundary finite element method (SBFEM) is used to solve the seepage problems with multi-material regions. Two models of dam base with waterproof screen and dam body with the regions of two materials are established. The numerical solutions are obtained and then compared with the analytical results or numerical solutions in the references. The conclusion shows that the SBFEM has more satisfactory accuracy and less data preparation amount.

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SCHAUER, MARCO, SABINE LANGER, JOSE E. ROMAN, and ENRIQUE S. QUINTANA-ORTÍ. "LARGE SCALE SIMULATION OF WAVE PROPAGATION IN SOILS INTERACTING WITH STRUCTURES USING FEM AND SBFEM." Journal of Computational Acoustics 19, no. 01 (March 2011): 75–93. http://dx.doi.org/10.1142/s0218396x11004316.

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This paper applies a parallel algorithm for a coupled Finite Element/Scaled Boundary Element (FEM/SBFEM)-approach to study soil-structure-interaction problems. The application code is designed to run on clusters of computers, and it enables the analysis of large-scale problems. A crucial point of the approach is that the SBFEM fulfills the radiation condition. Hence, the hybrid numerical approach is well suited for such problems where wave propagation to infinity in an unbounded domain must be considered. The main focus of the paper is to show the applicability of the numerical implementation on large scale problems. First the coupled FEM/SBFEM approach is validated by comparing the numerical results with a semi-analytical solution for a settlement problem. Then the implemented algorithm is applied to study the dynamical behavior of founded wind energy plants under time dependent loading.

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Lin, Gao, Wen-Bin Ye, Zhi-Yuan Li, and Jun Liu. "Analysis of spherical shell structure based on SBFEM." Engineering Computations 37, no. 6 (January 3, 2020): 2035–50. http://dx.doi.org/10.1108/ec-10-2019-0450.

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Purpose The purpose of this paper is to present an accurate and efficient element for analysis of spherical shell structures. Design/methodology/approach A scaled boundary finite element method is proposed, which offers more advantages than the finite element method and boundary element method. Only the boundary of the computational domain needs to be discretized, but no fundamental solution is required. Findings The method applies to thin as well as thick spherical shells, irrespective of the shell geometry, boundary conditions and applied loading. The numerical solution converges to highly accurate result with raising the order of high-order elements. Originality/value The modeling strictly follows three-dimensional theory of elasticity. Formulation of the surface finite elements using three translational degree of freedoms per node is required, which results in considerably simplifying the computation. In the thickness directions, it is solved analytically, no problem of high aspect ratio arises and transverse shear locking can be successfully avoided.

18

LEHMANN, L., S. LANGER, and D. CLASEN. "SCALED BOUNDARY FINITE ELEMENT METHOD FOR ACOUSTICS." Journal of Computational Acoustics 14, no. 04 (December 2006): 489–506. http://dx.doi.org/10.1142/s0218396x06003141.

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When studying unbounded wave propagation phenomena, the Sommerfeld radiation condition has to be fulfilled. The artificial boundary of a domain discretized using standard finite elements produces errors. It reflects spurious energy back into the domain. The scaled boundary finite element method (SBFEM) overcomes this problem. It unites the concept of geometric similarity with the standard approach of finite elements assembly. Here, the SBFEM for acoustical problems and its coupling with the finite element method for an elastic structure is presented. The achieved numerical algorithm is best suited to study the sound propagation in an unbounded domain or interaction phenomena of a vibrating structure and an unbounded acoustical domain. The SBFEM is applied to study the sound transmission through a separating component, and for the determination of the sound field around a sound insulating wall. The results are compared with a hybrid algorithm of Finite and Boundary Elements or with the Boundary Element Method, respectively.

19

Shi, Ming Guang, Chong Ming Song, Hong Zhong, Yan Jie Xu, and Chu Han Zhang. "A Coupled SBFEM-FEM Approach for Evaluating Stress Intensity Factors." Applied Mechanics and Materials 353-356 (August 2013): 3369–77. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.3369.

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A coupled method between the Scaled Boundary Finite Element Method (SBFEM) and Finite Element Method (FEM) for evaluating the Stress Intensity Factors (SIFs) is presented and achieved on the platform of the commercial finite element software ABAQUS by using Python as the programming language. Automatic transformation of the finite elements around a singular point to a scaled boundary finite element subdomain is realized. This method combines the high accuracy of the SBFEM in computing the SIFs with the ability to handle material nonlinearity as well as powerful mesh generation and post processing ability of commercial FEM software. The validity and accuracy of the method is verified by analysis of several benchmark problems. The coupled algorithm shows a good converging performance, and with minimum additional treatment can be able to handle more problems that cannot be solved by either SBFEM or FEM itself. For fracture problems, it proposes an efficient way to represent stress singularity for problems with complex geometry, loading condition or certain nonlinearity.

20

Chung, Nguyen Van, Nguyen Thanh Him, Bui Quoc Khiem, and Pham Ngoc Tien. "An effective high-order element for analysis of two-dimensional linear problem using SBFEM." Journal of Science and Technology in Civil Engineering (STCE) - NUCE 15, no. 3 (August 16, 2021): 109–22. http://dx.doi.org/10.31814/stce.nuce2021-15(3)-09.

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The scaled boundary finite element method (SBFEM) is a semi-analytical method, whose versatility, accuracy, and efficiency are not only equal to, but potentially better than the finite element method and the boundary element method for certain problems. This paper investigates the possibility of using an efficient high-order polynomial element in the SBFEM to form the approximation in the circumferential direction. The governing equations are formulated from the classical linear elasticity theory via the SBFEM technique. The scaled boundary finite element equations are formulated within a general framework integrating the influence of the distributed body source, mixed boundary conditions, contributions the side face with either prescribed surface load or prescribed displacement. The position of scaling center is considered for modeling problem. The proposed method is evaluated by solving two-dimensional linear problem. A selected set of results is reported to demonstrate the accuracy and convergence of the proposed method for solving problems in general boundary conditions.

21

Han, Jung Wan, Sung Noh Hong, Hyun Joo Jang, Seong Ran Jeon, Jae Myung Cha, Soo Jung Park, Jung Sik Byeon, et al. "Clinical Efficacy of Various Diagnostic Tests for Small Bowel Tumors and Clinical Features of Tumors Missed by Capsule Endoscopy." Gastroenterology Research and Practice 2015 (2015): 1–6. http://dx.doi.org/10.1155/2015/623208.

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Background. We aimed to evaluate the efficacy of various diagnostic tools such as computerized tomography (CT), small bowel follow-through (SBFT), and capsule endoscopy (CE) in diagnosing small bowel tumors (SBTs). Additionally, we aimed to evaluate the clinical features of SBTs missed by CE. Methods. We retrospectively studied 79 patients with histologically proven SBT. Clinical data were analyzed with particular attention to the efficacy of CT, SBFT, and CE in detecting SBT preoperatively. We also analyzed the clinical features of SBTs missed by CE. Results. The most common symptoms of SBT were bleeding (43%) and abdominal pain (13.9%). Diagnostic yields were as follows: CT detected 55.8% of proven SBTs; SBFT, 46.1%; and CE, 83.3%. The sensitivity for detecting SBTs was 40.4% for CT, 43.9% for SBFT, and 79.6% for CE. Two patients with nondiagnostic but suspicious findings on CE and seven patients with negative findings on CE were eventually found to have SBT. These nine patients were eventually diagnosed with gastrointestinal stromal tumor (4), small polyps (3), inflammatory fibroid polyp (1), and adenocarcinoma (1). These tumors were located in the proximal jejunum (5), middle jejunum (1), distal jejunum (1), and proximal ileum (1). Conclusion. CE is more efficacious than CT or SBFT for detecting SBTs. However, significant tumors may go undetected with CE, particularly when located in the proximal jejunum.

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Zunic, Marija, Aleksandra Milutinovic-Nikolic, Natasa Jovic-Jovicic, Predrag Bankovic, Zorica Mojovic, Dragan Manojlovic, and Dusan Jovanovic. "Modified bentonite as adsorbent and catalyst for purification of wastewaters containing dyes." Chemical Industry 64, no. 3 (2010): 193–99. http://dx.doi.org/10.2298/hemind091221023z.

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Modification and characterization of bentonite from location Bogovina, Serbia was performed in order to obtain material applicable in wastewater purification. The <75?m bentonite fraction was used in organobentonite synthesis while the <2?m bentonite fraction, obtained by hydroseparation was used in pillaring procedure. Organo-modification of bentonite was performed with (1-hexadecyl)trimethylammonium bromide (HDTMA-Br). Pillared bentonite was obtained using standard procedure. Al3+ and Fe3+ ions were incorporated in pillars in 4:1 ratio and applied as catalyst in catalytic wet peroxide oxidation. Differences in structure of starting and modified bentonites were established by XRD analysis and nitrogen physisorption on -196 ?C. The (001) smectite peak around 2? = 6? shifts during the modification process. The Na-exchange process lowered d001 from 1.53 nm (2? = 5.78?) for starting clay to 1.28 nm (2? = 6.92?), but the clay retained its swelling properties. The pillaring process increased and fixed the basal spacing to 1.74 nm. Intercalation of HDTMA ions into smectite structure increased d001 to 2.00 nm for organobentonite. Specific surface area, SBET, was affected by particle size and type of modification. The samples with finer bentonite fraction had higher SBET due to increased smectite content. Na-exchanged bentonite samples had higher SBET value than starting clay samples of same granulation. Organomodification caused dramatic decrease in SBET value, while the pillaring process lead to an increase of SBET value. Adsorptive and catalytic purification of wastewaters containing dyes was tested using Acid Yellow 99 as a model dye. Na-exchanged bentonite had greater adsorption affinity for dye adsorption than raw bentonite owing to higher SBET. By organomodification this affinity was enhanced more than 70 times due to transition of bentonite surface from hydrophilic to organophilic. Al,Fe pillared bentonite was proven to be efficient in catalytic wet peroxide oxidation of Acid Yellow 99 dye at room temperature.

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Yang, Yang, Zongliang Zhang, Yelin Feng, and Kun Wang. "A Novel Solution for Seepage Problems Implemented in the Abaqus UEL Based on the Polygonal Scaled Boundary Finite Element Method." Geofluids 2022 (March 10, 2022): 1–14. http://dx.doi.org/10.1155/2022/5797014.

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The scaled boundary finite element method (SBFEM) is a semianalytical computational scheme based on the characteristics of the finite element method (FEM) and boundary element method that combines their respective advantages. In this paper, the SBFEM and polygonal mesh technique are integrated into a new approach to solve steady-state and transient seepage problems. The proposed method is implemented in Abaqus employing a user-defined element (UEL). A detailed implementation of the procedure is presented in which the UEL element is defined, the internal variables RHS and AMATRX are updated, and the stiffness/mass matrix is solved using eigenvalue decomposition. Several benchmark problems are solved to verify the proposed implementation. The results show that the polygonal element of the polygonal SBFEM (PSBFEM) is more accurate than the standard FEM element of the same element size. For transient problems, the results for the PSBFEM and FEM are in excellent agreement. Hence, the proposed method is robust and accurate for solving steady-state and transient seepage problems. The developed UEL source code and the associated input files can be downloaded from GitHub.

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Li, Chao, and Liyong Tong. "2D fracture analysis of magnetoelectroelastic composites by the SBFEM." Composite Structures 132 (November 2015): 984–94. http://dx.doi.org/10.1016/j.compstruct.2015.07.015.

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25

Kaluža, Luděk, Martin Koštejn, and Daniela Gulková. "Deposition of Co onto Supported MoS2 by Water-Assisted Spreading: Increased Activity Promotion in Hydrodesulphurization of 1-Benzothiophene." Catalysts 9, no. 12 (November 25, 2019): 987. http://dx.doi.org/10.3390/catal9120987.

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Hydrodesulphurization (HDS) catalysts were newly prepared by water-assisted spreading of CoCO3.Co(OH)2 of low solubility in water onto pre-sulphided Mo species supported on several Al2O3 of surface area SBET 77-262 m2g−1, ZrO2 of SBET 108 m2g−1, and TiO2 of SBET 140 m2g−1. The spreading was followed by scanning electron microscopy (SEM-EDX). X-ray photoelectron spectroscopy (XPS) and temperature programmed reduction (H2-TPR) characterized partial re-oxidation of sulphidic Mo catalysts before Co sorption. The prepared catalysts were characterized in sulphidic form by H2-TPR. Activity of catalysts was determined in the HDS reaction of 1-benzothiophene. The spreading of Co onto sulphidic catalysts led to systematic increase of HDS activity by 16–86% in comparison to the spreading of Co onto oxide samples.

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Staňák, P., J. Sládek, V. Sládek, and S. Krahulec. "Numerical Evaluation Of Effective Thermal Properties For Materials With Variable Porosity." Building Research Journal 61, no. 3 (September 1, 2014): 129–42. http://dx.doi.org/10.2478/brj-2014-0010.

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Abstract In this paper a computational homogenization technique is applied to thermal analyses in porous materials. A volume fraction of pores on the microstructural level is the key factor that changes the macroscopic thermal properties. Thus, the distribution of thermal fields at the macroscopic level is analysed through the incorporation of the microstructural response on the representative volume element (RVE) assuming a uniform distribution of pores. For the numerical analysis the scaled boundary finite element method (SBFEM) is introduced to compute the thermal response of RVE. The SBFEM combines the main advantages of the finite element method (FEM) and the boundary element method (BEM). In this method, only the boundary is discretized with elements leading to the reduction of spatial dimension by one, similarly as in the BEM. It reduces computational efforts in the mesh generation and CPU time. The proposed method is used to study square RVE with a circular and elliptic pore under the thermal load. Dimensions of the pore are varied to obtain different volume fractions of matrix material. Numerical results for effective thermal conductivities obtained via SBFEM modelling show an excellent agreement with the finite element analysis using commercial software COMSOL Multiphysics.

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Concors, Seth Jason, Brett Ecker, Andrew Sinnamon, Douglas L. Fraker, Giorgos Karakousis, Charles M. Vollmer, and Robert Roses. "Survival after surgery for metastatic small bowel compared to pancreatic neuroendocrine tumors." Journal of Clinical Oncology 36, no. 4_suppl (February 1, 2018): 221. http://dx.doi.org/10.1200/jco.2018.36.4_suppl.221.

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221 Background: Surgical management of small bowel (mSBNET) and pancreatic (mPNET) neuroendocrine tumors with hepatic metastases remains controversial. Previous studies, often drawn from single institution experiences, combine outcomes mSBNET and mPNET cohorts, despite ample evidence indicating discreet biology and natural history. This study aimed to define and contrast survival outcomes after surgery in patients with mSBNET and mPNET using a large national dataset. Methods: Patients with hepatic metastases from SBNET and PNET who underwent surgical (n = 1063; n = 556, respectively) or non-surgical management (n = 456; n = 2593, respectively) were identified in the National Cancer Database (1998-2014). Surgical and non-surgical cohorts were matched (1:1) by propensity scores based on the likelihood of receiving surgery and survival hazard. Kaplan-Meier estimates of overall survival (OS) were compared. Results: After adjustment for potential cofounders (age, Charleston comorbidity index, tumor differentiation and administration of chemotherapy or radiotherapy), nonsurgical management was associated with poorer survival in SBNET (HR 2 95%CI 1.5-2.7) and in PNET (HR 3.6, 98%CI 2.8-4.5). In the propensity matched cohort, there was a significant survival advantage for patients who received surgery for both SBNET and PNET (p < 0.001). In SBNET, mean survival in the non-surgical cohort was 33.9 months (SD 1.3, 95%CI 31.5-36.4), and 39.3 months in the surgical cohort (SD 0.8, 95%CI 36.1-39.1). In PNET, mean survival in the non-surgical cohort was 32.7 months (SD 1.6, 95%CI 29.5-35.8), and 55.1 months in the surgical cohort (SD 1.4, 95%CI 52.4-57.7). Conclusions: Surgical selection or management are associated with a survival advantage in both mPNET and mSBNET; this advantage is greater in mPNET. The relative contributions of patient selection and therapeutic benefit require further elucidation.

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Huang, Yuan Feng, Wei Jun Zhang, Li Shen, Jin Hu, Zhuo Heng Li, Xiao Kun He, and Xu Xiao Yi. "Preparation and Characterization of the Typical Pt-NSR Catalyst." Advanced Materials Research 412 (November 2011): 365–69. http://dx.doi.org/10.4028/www.scientific.net/amr.412.365.

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A series of Ba-Al-O NSR supports and Pt/Ba-Al-O NSR catalysts are prepared by co-precipitation and impregnation method in this work. The catalyst and the support are characterized by XRD, SEM, SBET performance testing. The structure and texture of the supports is observed and discussed. The results of SBET indicate that the supports possess relative high specific surface area (94~110 m2/g). Temperature programmed reduction is characterized by means of H2-TPR.

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Manguso, Nicholas, Jeffrey Johnson, Attiya Harit, Nicholas Nissen, James Mirocha, Andrew Hendifar, and Farin Amersi. "Prognostic Factors Associated with Outcomes in Small Bowel Neuroendocrine Tumors." American Surgeon 83, no. 10 (October 2017): 1174–78. http://dx.doi.org/10.1177/000313481708301033.

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Small bowel neuroendocrine tumors (SBNET) account for most gastrointestinal neuroendocrine tumors. Patients often present with late-stage disease; however, there is little information regarding factors that contribute to recurrence. Database review identified 301 patients diagnosed with SBNET between 1990 and 2013. Univariate analysis included patients who underwent complete resection. Survival was estimated by the Kaplan–Meier method. A total of 147 patients met study criteria. Average age was 60 years (range 21–91); 49 per cent were male. Thirty-seven (25.3%) patients had laparoscopic resection, and 29 (19.9%) patients had only small bowel disease, whereas 108 (72.6%) had nodal metastasis. Five-year overall and disease-free survival were 97.5 and 73.5 per cent. Forty-seven (32%) patients had recurrence. The recurrence group was more likely to have an open operation (59.6 vs 32%, P < 0.01), mesenteric invasion, or lymphatic metastasis (87.2 vs 67%, P < 0.01) compared with the no-recurrence group. Cox regression analysis showed that variables associated with recurrence included nodal disease (HR 9.06, P = 0.03), lymphovascular invasion (LVI) (3.95, P < 0.01), perineural invasion (PNI) (3.48, P < 0.01), and mesenteric involvement (3.77, P = 0.03). Patients with SBNET presenting with nodal metastasis, mesenteric involvement, LVI, or PNI have a higher risk of recurrence. Closer surveillance should be considered after operative resection.

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Jung, Jonathan Daniel, and Wilfried Becker. "SBFEM elements for thin-walled composite beams with arbitrary layup." PAMM 14, no. 1 (December 2014): 267–68. http://dx.doi.org/10.1002/pamm.201410121.

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Gravenkamp, Hauke, Sascha Duczek, and Carolin Birk. "Automatic quadtree-based modeling using a coupled SBFEM/SCM approach." PAMM 17, no. 1 (December 2017): 299–300. http://dx.doi.org/10.1002/pamm.201710119.

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Sladek, Jan, Vladimir Sladek, Slavomir Krahulec, and Chongmin Song. "Crack analyses in porous piezoelectric brittle materials by the SBFEM." Engineering Fracture Mechanics 160 (July 2016): 78–94. http://dx.doi.org/10.1016/j.engfracmech.2016.03.046.

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Li, Chao, Ean Tat Ooi, Chongmin Song, and Sundararajan Natarajan. "SBFEM for fracture analysis of piezoelectric composites under thermal load." International Journal of Solids and Structures 52 (January 2015): 114–29. http://dx.doi.org/10.1016/j.ijsolstr.2014.09.020.

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Khudari Bek, Y., K. M. Hamdia, T. Rabczuk, and C. Könke. "Micromechanical model for polymeric nano-composites material based on SBFEM." Composite Structures 194 (June 2018): 516–26. http://dx.doi.org/10.1016/j.compstruct.2018.03.064.

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Li, Chao, and Liyong Tong. "Topology optimization of incompressible materials based on the mixed SBFEM." Computers & Structures 165 (March 2016): 24–33. http://dx.doi.org/10.1016/j.compstruc.2015.12.003.

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Amin, Anwar, Laila I. Ali, and Anwar M. Ibrahim. "Compaction versus Surface Parameters of Certain Solid Catalysts." Adsorption Science & Technology 15, no. 4 (April 1997): 323–31. http://dx.doi.org/10.1177/026361749701500407.

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The effect of compaction at 0.31–3.1 t/cm2 on Al(OH)3, Mg(OH)2 and their mixed hydroxide was studied by nitrogen adsorption. With Al(OH)3, compaction gave no significant changes up to 1.24 t/cm2, but above 1.55 t/cm2 a considerable decrease in SBET and an increase in pore radius occurred with small changes in pore volume. This could be ascribed to the presence of free water between the structural layers in the material which normally prevents their contact and a consequent destruction of the pore structure. With Mg(OH)2, compaction at low pressures decreased SBET and increased the pore dimensions as a result of adhesion between neighbouring particles, leading to a blocking of that fraction of the micropore structure originally accessible to nitrogen molecules. Increasing compaction led to a marked increase in the adsorption capacity as a consequence of plastic deformation associated with the breakage of fragile primary particles and the creation of new surfaces. Compaction of the mixed hydroxide led at first to an increase in both the SBET and Vp values (due to fragmentation of the particles), followed by a loss of SBET due to the presence of a mixture of particles in the system which increase the compression ability of the latter. Complete pore structure analysis showed that samples of Al(OH)3 powder when compacted at 0.31 and 1.55 t/cm2 were microporous. All other samples contained mainly mesopores.

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El-Shobaky, G. A., and Kh A. Khalil. "Surface Characteristics of the Pure and Li2O-doped MoO3/Al2O3 System." Adsorption Science & Technology 16, no. 2 (March 1998): 127–34. http://dx.doi.org/10.1177/026361749801600206.

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Two series of MoO3/Al2O3 solids, having the nominal compositions 0.2MoO3: Al2O3 and 0.5MoO3:A12O3, were prepared by impregnating finely powdered Al(OH)3 samples with calculated amounts of ammonium molybdate solutions. The solids thus obtained were dried at 120°C and then calcined in air at temperatures varying between 400°C and 1000°C. The doped samples were prepared by treating Al(OH)3 with LiNO3 solutions prior to impregnation with ammonium molybdate. The dopant concentrations employed were 1.5 and 6.0 mol% Li2O, respectively. The surface characteristics, viz. the specific surface area (SBET), the total pore volume (VP) and the mean pore radius (r) of the various pure and doped solids were measured from nitrogen adsorption isotherms conducted at -196°C. The SBET data measured for different adsorbents calcined at various temperatures enabled the apparent activation energy for sintering (ΔE3) to be determined for all the adsorbents investigated. The results obtained reveal that the SBET value of the pure and doped solids decreased on increasing the calcination temperature in the range 400–1000°C. The decrease was, however, more pronounced when the calcination temperature increased from 500°C to 700°C due to the formation of Al2(MoO4)3. Lithium oxide doping decreased the SBET value of the solid samples investigated and also decreased the activation energy for sintering to an extent proportional to the amount of dopant present. The sintering process for the pure and doped solids proceeds, mainly, via a particle adhesion mechanism.

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Khalil, Kh A. "Surface Characteristics of Portland Cement/Blast Furnace Slag Mixtures." Adsorption Science & Technology 13, no. 6 (December 1996): 461–67. http://dx.doi.org/10.1177/026361749601300602.

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The effect of the degree of hydration and amounts of granulated blast furnace slag on the surface properties of Portland cement pastes were studied. The results obtained showed that the specific surface area SBET (m2/g) and pore volume Vp (cm3/g) decreased on increasing the degree of hydration. The addition of different amounts of granulated slag effected a decrease in SBET and Vp to an extent proportional to the amount present. These results were attributed to a replacement of clinker by the amounts of slag added and the formation of hydration products.

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Shen, Xiaowei, Haowen Hu, Zhongwang Wang, Xiuyun Chen, and Chengbin Du. "Stochastic Fracture Analysis Using Scaled Boundary Finite Element Methods Accelerated by Proper Orthogonal Decomposition and Radial Basis Functions." Geofluids 2021 (September 4, 2021): 1–15. http://dx.doi.org/10.1155/2021/9181415.

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This paper presents a stochastic analysis method for linear elastic fracture mechanics using the Monte Carlo simulations (MCs) and the scaled boundary finite element method (SBFEM) based on proper orthogonal decomposition (POD) and radial basis functions (RBF). The semianalytical solutions obtained by the SBFEM enable us to capture the stress intensity factors (SIFs) easily and accurately. The adoption of POD and RBF significantly reduces the model order and increases computation efficiency, while maintaining the versatility and accuracy of MCs. Numerical examples of cracks in homogeneous and bimaterial plates are provided to demonstrate the effectiveness and reliability of the proposed method, where the crack inclination angles are set as uncertain variables. It is also found that the larger the scale of the problem, the more advantageous the proposed method is.

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Saleem, Muhammad. "Effect of Chemical Activating Agents on Surface Area and Methylene Blue Uptake Capacity of Activated Carbons." Pakistan Journal of Scientific & Industrial Research Series A: Physical Sciences 64, no. 3 (September 29, 2021): 254–64. http://dx.doi.org/10.52763/pjsir.phys.sci.64.3.2021.254.264.

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Activated carbon from Acacia asak (Fabaceae) tree branches was prepared utilizing three-steps- process and H3P04, ZnCl2, H2S04, K2C03, Na0H and K0H as chemical activating agents. In addition to the elemental analysis of precursor materials, produced activated carbon (ATB-AC) was also analyzed for moisture content, ash content, pH value, bulk density, volatile matter, hardness, specific surface area (SBET), iodine number and pore volume. Results revealed that the quality of ATB-AC is well comparable to the available commercial activated carbon (CAC). The SBET was found to be in the order of ATB-AC1> ATB- AC2> ATB-AC4> ATB-AC6> ATB-AC3> ATB-AC5. All the produced ATB-AC demonstrated good MB (methylene blue) removal efficiency, whereas ATB-AC1 and ATB-AC2 (produced from H3P04, and ZnCl2) showed higher efficiency. It is concluded that the chemical activating agent has significant effect on produced AC keeping all other production parameters constant. Among the six studied chemicals, H3P04 and ZnCl2 produced AC exhibited high SBET surface area and MB uptake capacity.

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El-Salaam, K. M. Abd, and A. M. El-Awad. "Texture Studies on Chromium Oxide Doped Catalysts." Adsorption Science & Technology 4, no. 1-2 (March 1987): 131–39. http://dx.doi.org/10.1177/0263617487004001-212.

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Physisorption of N2 gas at 77 K has been used to determine the surface area (SBET) and porosity of Cr2O3 impregnated with Li2O in molar ratios extending from 0.25 to 50 mol %. Calcination of catalysts was affected in air flow in temperature range of 473-773 K. Variation of the SBET-calcination temperature relationship was interpreted according to the possible lattice rearrangements via a solid-state reaction leading to Li2CrO4 phase formation for Li2O rich samples and by creation of cation vacancies in case of Li2O trace samples. The cumulative calculations together with Va-t plots showed a mesoporous surface nature of samples.

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Abe, H., T. Yamada, M. Ogiwara, T. Tsuruoka, K. Hashimoto, and R. Kawasaki. "A superconducting-base hot-electron transistor (SBHET) using a high-Tcsuperconductor." Superconductor Science and Technology 4, no. 11 (November 1, 1991): 598–601. http://dx.doi.org/10.1088/0953-2048/4/11/011.

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Yao, F., Z. J. Yang, and Y. J. Hu. "An SBFEM-Based Model for Hydraulic Fracturing in Quasi-Brittle Materials." Acta Mechanica Solida Sinica 31, no. 4 (May 17, 2018): 416–32. http://dx.doi.org/10.1007/s10338-018-0029-3.

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Gravenkamp, Hauke, and Sascha Duczek. "Automatic image-based analyses using a coupled quadtree-SBFEM/SCM approach." Computational Mechanics 60, no. 4 (June 2, 2017): 559–84. http://dx.doi.org/10.1007/s00466-017-1424-1.

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45

Li, Chao, and Liyong Tong. "A mixed SBFEM for stress singularities in nearly incompressible multi-materials." Computers & Structures 157 (September 2015): 19–30. http://dx.doi.org/10.1016/j.compstruc.2015.05.011.

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46

Liu, Dan Dan, De Ren Miao, and Fei Liu. "Evaluation of the As, Cu and Pb Immobilizing Efficiency by Tessier, TCLP and SBET Method." Advanced Materials Research 878 (January 2014): 520–31. http://dx.doi.org/10.4028/www.scientific.net/amr.878.520.

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Utilize of property evaluation method for an immobilizing procedure is very important. In this paper, an immobilizing procedure was used to stabilize heavy metals in tested soils. Tessier sequence extract procedure (SEP), toxicity leaching procedure (TCLP) and simple bioaccessibility extraction test (SBET) were used to evaluate the efficiency of the stabilization procedure. The leachability, bioaccessibility and speciation of As, Cu and Pb in the tested soils were analyzed using Tessier SEP, TCLP and SBET method separately. The results indicated that the most active part of the heavy metals could be extracted out by TCLP method and it could be used to evaluate the risk of the tested soils. Tessier method divided heavy metals in soils to different fractions. Monitoring the changes of different fractions during the immobilizing procedure could help fully understand the mechanism of stabilization. The SBET method simulated the human digest system and evaluated the risk changes to human during the immobilizing procedure. And it helped to reveal the potential risk of chemical stability. In our project, these three evaluation method should be utilized properly to help accessing the risk, electing suitable immobilizing method and evaluating the efficiency of stabilization.

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Zhao, Nan, Xiao Jun He, Ping Hua Ling, Ru Chin Li, Mo Xin Yu, Xiao Yong Zhang, and Ming Dong Zheng. "Facile Preparation of Microporous Carbons with High Specific Capacitance from Coal Tar Pitch for Supercapacitors." Advanced Materials Research 557-559 (July 2012): 1205–9. http://dx.doi.org/10.4028/www.scientific.net/amr.557-559.1205.

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Microporous carbons (MCs) for supercapacitors were prepared from coal tar pitch (CTP) with potassium hydroxide (KOH) as activating agent at different KOH/CTP mass ratio by different heating modes. The results show that the specific surface area (SBET), micropore surface area (Smic), total pore volume (Vt) and micropore volume ((Vmic) of MCs made by microwave heating at 30 min heating time increases with the KOH/CTP mass ratio, respectively. At 14/7 of the KOH/CTP mass ratio, the SBET of MCs made by microwave heating at 30 min heating time reaches 1786 m2/g while that of MCs made by conventional heating at 180 min heating time is 1769 m2/g. The specific capacitance and energy density of the former reaches 269 F/g and 9.2 Wh/kg in 6 M KOH aqueous electrolyte while that of the latter is up to 307 F/g and 10.5 Wh/kg, respectively. And yet, the former brings bigger MC yield and bigger retention of energy density. The effects of the pore size distribution and pore volume on the specific capacitance and energy density of MC samples with the similar SBET by different heating modes are addressed in this paper.

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Deng, Hongyan, Haixia He, Wenbin Li, Touqeer Abbas, and Zhifeng Liu. "Characterization of amphoteric bentonite-loaded magnetic biochar and its adsorption properties for Cu²⁺ and tetracycline." PeerJ 10 (March 1, 2022): e13030. http://dx.doi.org/10.7717/peerj.13030.

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To realize simultaneous adsorption of heavy metal and antibiotic pollutants by a BC-based recyclable material, Fe3O4 magnetic biochar (MBC) was prepared by co-precipitation method. Then different ratios of dodecyl dimethyl betaine (BS-12)-modified bentonite (BS-B) were loaded on the surfaces of biochar (BC) and MBC to prepare BS-B-loaded BC and MBC composites, called BS-B/BC and BS-B/MBC, respectively. The physicochemical and structural properties of the composites were characterized by scanning electron microscopy, Fourier transform infrared spectrometry, thermogravimetric analysis, specific surface area (SBET) analysis, and vibrating sample magnetometry, and the adsorption efficiencies of BS-B/BC and BS-B/MBC to Cu2+ and tetracycline (TC) were studied. The following results were obtained. (1) Compared with BS-B/BC, BS-B/MBC had decreased pH and cation exchange capacity (CEC) and increased SBET. The pH, CEC, and SBET of BS-B/BC and BS-B/MBC decreased with the increase in the BS-12 proportion of BS-B. The surface of BS-B/MBC became rough after Fe3O4 loading. (2) The residual rate of BS-B/MBC was higher than that of BS-B/BC after high-temperature combustion, and the residual rate decreased with the increase in the BS-12 proportion of BS-B. The 2D infrared spectra showed that Fe3O4 and BS-12 were modified on the surface of BS-B/MBC. MBC and BS-B/MBC had splendid magnetism and could be separated by external magnetic field. (3) Compared with unmagnetized ones, the adsorption effects of Cu2+ and TC on different BS-B/MBCs improved, and the average adsorption rate reached the largest value of 91.92% and 97.76%, respectively. Cu2+ and TC adsorptions were spontaneous, endothermic, and entropy-increasing processes. The pH and SBET of the material had a great influence on Cu2+ and TC adsorptions, respectively, than CEC.

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Qiu, Yingnan, Na Ye, Danna Situ, Shufeng Zuo, and Xianqin Wang. "Study of Catalytic Combustion of Chlorobenzene and Temperature Programmed Reactions over CrCeOx/AlFe Pillared Clay Catalysts." Materials 12, no. 5 (March 2, 2019): 728. http://dx.doi.org/10.3390/ma12050728.

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In this study, both AlFe composite pillaring agents and AlFe pillared clays (AlFe-PILC) were synthesized via a facile process developed by our group, after which mixed Cr and Ce precursors were impregnated on AlFe-PILC. Catalytic combustion of organic pollutant chlorobenzene (CB) on CrCe/AlFe-PILC catalysts were systematically studied. AlFe-PILC displayed very high thermal stability and large BET surface area (SBET). After 4 h of calcination at 550 °C, the basal spacing (d001) and SBET of AlFe-PILC was still maintained at 1.91 nm and 318 m2/g, respectively. Large SBET and d001-value, along with the strong interaction between the carrier and active components, improved the adsorption/desorption of CB and O2. When the desorption temperatures of CB and O2 got closer to the CB combustion temperature, the CB conversion could be increased to a higher level. CB combustion on CrCe/AlFe-PILC catalyst was determined using a Langmuir–Hinshelwood mechanism. Adsorption/desorption/oxidation properties were critical to design highly efficient catalysts for CB degradation. Besides, CrCe/AlFe-PILC also displayed good durability for CB combustion, whether in a humid environment or in the presence of volatile organic compound (VOC), making the catalyst an excellent material for eliminating chlorinated VOCs.

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Hell, Sascha, and Wilfried Becker. "Hypersingularities in Three-Dimensional Crack Configurations in Composite Laminates." Key Engineering Materials 577-578 (September 2013): 209–12. http://dx.doi.org/10.4028/www.scientific.net/kem.577-578.209.

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Composite laminates meanwhile are of common use, especially in aerospace engineering. Inter-fiber cracks within a laminate ply are often accepted in practice to be still within failure tolerance, although the structural mechanics of this situation is not fully understood. The situation gets even more complex when the interaction of inter-fiber cracks in neighboring plies is considered. In this work, such three-dimensional crack configurations in composite laminates involving inter-fiber cracks and the influence of the laminate free-edge effect are studied by means of the Scaled Boundary Finite Element Method (SBFEM). The SBFEM is an efficient semi-analytical method that permits the analysis of linear elasticity problems including stress singularities or infinite domains. It is shown that in crack configurations in composite laminates so-called hypersingularities (or supersingularities) can occur, i.e. stress singularities which are of higher order than the classical crack singularity. This indicates that the laminate failure risk induced by certain considered crack configurations is not to be underestimated.

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