To see the other types of publications on this topic, follow the link: Number of openings.
Journal articles on the topic 'Number of openings'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Number of openings.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Badarloo, Baitollah, and Faezeh Jafari. "A Numerical Study on the Effect of Position and Number of Openings on the Performance of Composite Steel Shear Walls." Buildings 8, no. 9 (2018): 121. http://dx.doi.org/10.3390/buildings8090121.
Full textAbstract:
Use of composite steel shear walls (CSSW) in earthquake-resistant structures has grown in recent years. However, no thorough information exists on their performance, especially in cases where openings are present. In the present study, in order to first validate the analysis method, ABAQUS was used to model the studied composite shear wall with gap at UC-Berkeley, according to the results of which, a good agreement between the experimental and analytical models was observed. Then, the effect of the position and number of the openings on the performance of the walls was addressed. To this end, models with various openings, including openings close to the beam/column, horizontal/vertical openings and distributing opening, were prepared and analyzed. The results indicate that the maximum reduction in stiffness and strength occurred in walls with single openings. The size of opening and the opening’s area significantly affect shear wall performance. Ultimately, artificial neural network and fitness function tools were employed to obtain predictive models for shear wall performance. A neural network has proven an appropriate alternative method for predicting the displacement, stress, and strength of the composite shear wall.
2
Waleed Kh. Hadi and May J. Hamoodi. "Experimental Study on Composite Beams with Circular Web Openings." University of Thi-Qar Journal for Engineering Sciences 5, no. 1 (2014): 43–54. http://dx.doi.org/10.31663/utjes.v5i1.611.
Full textAbstract:
The behavior of composite beams with circular web openings is described. Four composite beams comprising one control beam were tested. The perforated beams have six circular openings with various locations. Opening size was fixed (66.7% of the steel section web depth) while number of openings in each composite beam was varied. Deflections at midspan and at openings were observed. Cracking of concrete slab and behavior of each opening were explained in detail. Tests indicated that circular web opening reduced the strength of composite beams. The behavior of composite beams relatively unaffected by the presence of circular web openings up to first yield. Less effect for the inclusion of circular web openings located out of midspan. The concrete slab has limited contribution to the strength of composite beams with circular web openings.
3
Meyoof, Tareq R., Amer F. Izzet, and Majid M. Kharnoob. "Performance of reinforced concrete non-prismatic beams having multiple openings configurations." Journal of the Mechanical Behavior of Materials 31, no. 1 (2022): 381–89. http://dx.doi.org/10.1515/jmbm-2022-0043.
Full textAbstract:
Abstract This experimental study demonstrates the gable-reinforced concrete beams’ behavior with several number of openings (six and eight) and posts’ inclination, aimed to find the strength reduction in this type of beam. The major results found are: for the openings extending over similar beam length it is better to increase the number of posts (openings), i.e., increasing opening number led to decrease in opening area, which allows us to transmit stresses and act as lever arms between the upper and the lower chords. Also, findings revealed that the inclined posts have larger loading at the mid-point relative to vertical ones. For gables with vertical posts having six and eight openings, the ultimate strength reduction was 31.5 and 25.6%, whereas it was 29 and 17.3% for those with inclined posts, respectively.
4
Ali, Hasan Hussein, and Abdul Muttailb I. Said. "Flexural behavior of concrete beams with horizontal and vertical openings reinforced by glass-fiber-reinforced polymer (GFRP) bars." Journal of the Mechanical Behavior of Materials 31, no. 1 (2022): 407–15. http://dx.doi.org/10.1515/jmbm-2022-0045.
Full textAbstract:
Abstract This study conducted an analytical investigation on the behavior of concrete beams with openings reinforced by glass-fiber-reinforced polymer (GFRP) bars. In this study, five proposed beams reinforced by GFRP bars as flexural and shear reinforcement with openings were numerically examined. The variables were the opening orientation (vertical and horizontal) and the number of openings. These openings were located within the flexural zone of the proposed beams. The result shows that the vertical openings had a significant effect over the horizontal openings on reducing the ultimate load and increasing the mid-span deflection compared with the control beam. Moreover, the results showed that when replacing two adjacent openings by one equivalent opening, the capacity of the beam is decreased.
5
Nie, Xuefei, Shishun Zhang, Zeyu Gao, and Zhuo Zeng. "A review on the behaviour of reinforced concrete beams with fibre-reinforced polymer-strengthened web openings." Advances in Structural Engineering 25, no. 2 (2021): 426–50. http://dx.doi.org/10.1177/13694332211046344.
Full textAbstract:
Web openings often need to be created in reinforced concrete (RC) beams for the passages of utility ducts and/or pipes. Such web openings reduce the cross-section area of the beam in the affected region, leading to decrease in its load-carrying capacity and stiffness. Therefore, a fibre-reinforced polymer (FRP)-strengthening system generally needs to be applied around the web opening to ensure the safety of the weakened beam. A number of studies have been conducted by researchers all over the world to examine the behaviour of RC beams with FRP-strengthened web opening/web openings, and plenty of useful findings have been generated. This article presents a critical literature review of existing relevant research from three aspects: experimental studies, numerical studies and theoretical studies. The effect of main factors, including the size, shape, location and number of the web opening, the shape and shear span ratio of the beam, the concrete strength, the loading scheme and the FRP-strengthening scheme, on the structural performance of RC beams with FRP-strengthened web opening/web openings have been thoroughly analysed and discussed. Finally, directions for future research based on the gaps which exist in existing studies are pointed out.
6
AlJallad, Sadjad Amir, and Haitham Al-Thairy. "EFFECT OF WEB OPENING ON THE AXIAL LOAD CAPACITY OF STEEL COLUMNS WITH COLD FORMED THIN WALLED SECTION (CFS)." Kufa Journal of Engineering 7, no. 3 (2016): 13–26. http://dx.doi.org/10.30572/2018/kje/731200.
Full textAbstract:
In this paper, an experimental study has been presented to investigate the effects of web opening on the behavior and failure of steel columns with cold formed thin walled sections (CFS) subjected to axial compressive load. Twenty small scale steel columns with cold formed box and channel sections and a total length of 500 mm have been considered in the experimental tests. Ten of the tested steel columns specimens have a box section with dimensions of (100×100×2) mm (height × width× thickness), and the other ten columns specimens have a channel sections with dimensions of (100×50×2) mm (height × width× thickness). To investigate the effect of the number and the shape of web opening on the axial compressive strength of steel columns, each ten columns with same cross section shape was divided into three groups of three columns in addition to the reference column which has no web openings. All groups of columns have same opening area which is located at the web of the section, but each group has a different opening shape (square, rectangular, and circular shapes), and each steel column within each group has different numbers of opening distributed along column length (one, two, and three openings). Each steel column specimens was subjected to an increasing static load up to column failure which indicated by the reloading of the test machine. The study has shown that for most of the tested columns, increasing the numbers of web openings results in decreasing the column axial strength compared to the reference steel column. The maximum percentage of the reduction in the columns axial compressive strength caused by the presence of web opening was found to be about 30% and 45% of the reference columns strength for columns with box and channel shape sections, respectively. It has also been found that the reduction in the axial compressive strength of the column specimens caused by the presence of web openings is lower for the circular shape openings compared to that for rectangular and/or square shape web openings.
7
Doshi, Akash, and Rebecca Shadowen. "Opening Doors in the Operating Rooms: An Intervention and Outcome Study." Infection Control & Hospital Epidemiology 41, S1 (2020): s336. http://dx.doi.org/10.1017/ice.2020.943.
Full textAbstract:
Background: Surgical site infections (SSIs) are a major cause of morbidity and mortality with an estimated cost of $3–10 billion annually in the United States. Laminar air flow in the operating room (OR) is 1 factor in reducing SSIs. Opening the OR door results in interruption of laminar air flow. As a part of annual infection prevention evaluation of our facility, we observed cases in the OR in which we identified excessive unnecessary door openings during surgical cases. We report an intervention in door openings in the OR and the effect on infection rate after surgery. Methods: We conducted an observational analytical study using prospective audit and feedback. Door-opening counters were placed on 4 OR doors. Each day, they were reset and the number was logged for each case by the circulating nurse. A baseline number of door openings was established between April 18, 2019, and May 2, 2019. Subsequently, daily feedback sheets were provided to all persons involved in the previous day’s procedures detailing the rationale to limit unnecessary door openings and the number of door openings that had occurred during the case(s) in which they were specifically involved from May 3, 2019, to June 4, 2019. Analyses of postoperative infection rates compared with historical controls were conducted. Using Stata version 15 statistical software, independent sample t tests were performed to see the difference between control and intervention groups. A CI 95% was set for significance. Results: There were no differences between control and intervention groups with the number of procedures (71 vs 80), OR, duration of procedure, or type of case. Outliers due to vibration of doors triggering the counters were removed, and door stabilizations were performed throughout the study. After removing outliers, there were no differences in control groups and interventions groups (39 vs 43). An independent sample t test showed a significant difference in the mean number of door openings between the control and intervention groups: 32.13 versus 24.84 (P < .05 and P = .0072). There have been no postoperative infections in any of the cases in the study to date compared to an overall annual rate of 1.5% in 2018 at our facility. Conclusions: Prospective audit and feedback to OR staff can reduce the number of unnecessary door openings during operating procedures. The baseline number of door openings from this study was 25 per case. No postoperative infections occurred in the patients receiving surgery in this study.Funding: NoneDisclosures: None
8
Jarallah, Husain Khalaf, and Nidaa Qassim Jassim. "Ductility Improvement of R.C Beams with Large Web opening by using Reactive Powder Concrete Layers." Tikrit Journal of Engineering Sciences 25, no. 3 (2018): 30–39. http://dx.doi.org/10.25130/tjes.25.3.06.
Full textAbstract:
In this investigation the effect of large web opening on the on the behaver of beams made by normal concrete (NC) and reactive powder concrete (RPC) have been studied. The experimental work consists of casting and testing in flexure 12 rectangular simply supported reinforced concrete beams. The main parameters of this test are opening locations and normal concrete and RPC location with is the section. The ultimate loads, cracking loads, load -deflection behavior, skew of the openings (deflection at the two opposite corners of openings) and ductility were discussed. These results showed that increase ultimate loads (Pu) and stiffness by increase RPC layers. The using RPC layers increase ultimate load about (1-30) %. Using RPC in compression fiber is found to be more effective than using RPC in tension fiber. The cracking load of hybrid beam with one layer of RPC in compression fiber (having one opening) higher than NC beams by 48.5%. The ultimate strength was decreases with increases opening about (4-21)%, thus indicating that the stiffness decreases accordingly. Hybrid beams with RPC in tension fiber failed with less crack than those for hybrid beams with RPC in compression fiber at the same number of openings. The skew at opening of flexural zone show greater values than the skew at opening in shear zone for each beam until failure. The increase in the number of openings leads to increase in the ductility because it reduces the strength of beams.
9
Ali, Hasan Hussein, and Abdulmuttailb I. Said. "Experimental Study on the Performance of Concrete Beams Including Holes Reinforced with Glass Fiber Polymer." E3S Web of Conferences 427 (2023): 02010. http://dx.doi.org/10.1051/e3sconf/202342702010.
Full textAbstract:
This paper carried out An examination of the performance characteristics of concrete beams including openings that were reinforced with Glass Fiber Reinforced Polymer (GFRP) bars. This investigation studied five reinforced concrete (RC) beams with both longitudinal and transverse GFRP reinforcement with openings in two directions (horizontal and vertical) were studied. Both the orientation of the openings and the number of openings were considered to be the main parameters in this research. These holes are located in the beams' flexural region. The results demonstrate that relative to the reference beam, the vertical openings significantly reduced the maximum load of the tested beams by 27.8% and increased the mid-span displacement by 39% relative to the control beam. In addition, the research results demonstrated that the strength of the beam was scaled down if one equivalent opening was used to substitute for two adjacent openings.
10
Colleu, T., and S. Benitez. "RAY-BASED DETECTION OF OPENINGS IN URBAN AREAS USING MOBILE LIDAR DATA." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B3 (June 9, 2016): 591–98. http://dx.doi.org/10.5194/isprs-archives-xli-b3-591-2016.
Full textAbstract:
The detection of openings like windows or doors is of great interest in the field of urban modeling. Mobile LIDAR data provides valuable 3D information for that purpose. There are generally two main problems: The estimation of wall’s surface, and the distinction between opening areas and occluded areas. Indeed, openings may be visible or occluded with regard to the sensor. The method presented in this paper focuses on the detection of visible openings using intersections between laser rays and walls. In particular, it shows that detection of visible openings can be reduced to a single distance threshold once the surface of the wall is computed. Thus all the complexity is actually in the estimation of the wall’s surface. The opening contours are then obtained by clustering the visible opening points and fitting them with rectangles. The main advantage of ray-based detection is its robustness to occlusions. This method requires the LIDAR sensor positions and angles for every laser point. Results are evaluated quantitatively on two datasets with ground truth. Qualitative results on larger datasets are also given. The results show good precision. The recall (or completeness) depends on the number of occluded openings.
11
Colleu, T., and S. Benitez. "RAY-BASED DETECTION OF OPENINGS IN URBAN AREAS USING MOBILE LIDAR DATA." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B3 (June 9, 2016): 591–98. http://dx.doi.org/10.5194/isprsarchives-xli-b3-591-2016.
Full textAbstract:
The detection of openings like windows or doors is of great interest in the field of urban modeling. Mobile LIDAR data provides valuable 3D information for that purpose. There are generally two main problems: The estimation of wall’s surface, and the distinction between opening areas and occluded areas. Indeed, openings may be visible or occluded with regard to the sensor. The method presented in this paper focuses on the detection of visible openings using intersections between laser rays and walls. In particular, it shows that detection of visible openings can be reduced to a single distance threshold once the surface of the wall is computed. Thus all the complexity is actually in the estimation of the wall’s surface. The opening contours are then obtained by clustering the visible opening points and fitting them with rectangles. The main advantage of ray-based detection is its robustness to occlusions. This method requires the LIDAR sensor positions and angles for every laser point. Results are evaluated quantitatively on two datasets with ground truth. Qualitative results on larger datasets are also given. The results show good precision. The recall (or completeness) depends on the number of occluded openings.
12
Jiang, Xintong, Hanbo Cui, Shenghao Guo, and Zongyun Mo. "Influence of openings on the snowdrift characteristics of cubes." PLOS One 20, no. 6 (2025): e0325545. https://doi.org/10.1371/journal.pone.0325545.
Full textAbstract:
Snow drifts and accumulates under wind actions, leading to a complex distribution of snow around and on the surface of structures with openings, which in turn has a detrimental influence on the structures. There is no relevant code provision for this situation. Therefore, a wind tunnel study was carried out to experimentally investigate how opening size and vertical location (for cubes with single openings) and how the relative positions of different openings (for cubes with multiple openings) influenced the wind-induced snowdrifts around and on the surface of cubes with openings. A roughness coefficient was introduced to characterize the snow around cubes. It was found that snow accumulation at the side of the cube produced a greater uneven snow load. The number and vertical location of openings were the main factors influencing the roughness of the snow. The snow depth coefficient (Cs) around and on the surface of a cube is approximately negatively correlated with opening size and approximately positively correlated with opening vertical location. The simultaneous existence of openings on the windward, side and top faces of a cube adversely affected the safety of the surroundings of the cube. The variation pattern of fractal characteristic of particles, D, was similar to that of Cs when the snow was fully eroded at the windward corner of the cube. These findings will help improve the accuracy of snow distribution pattern prediction and enhance the safety and rationality of the structural design of buildings.
13
Nasr, Nasr E., M. N. Fayed, Gamal Hussien, and A. M. El-Makhlasawi. "The Effect of Shear Wall Openings on the Response Reduction Factor." Civil Engineering Journal 8, no. 4 (2022): 796–822. http://dx.doi.org/10.28991/cej-2022-08-04-013.
Full textAbstract:
This research attempts to investigate the effect of shear wall openings on the response reduction factor. Openings are commonly necessary because of other engineering disciplines’ requirements. When openings are modest in proportion to the size of the wall, their effects are frequently disregarded. On the other hand, when these openings are large or located in a high-risk area, they can have a significant impact. A broad literature review has been conducted in the present study. A verified comparative example consisting of eight stories was studied. Then, a numerical study has been conducted on two different model sets with 16 and 8 stories, which were designed according to the Egyptian code of loads, ECP-201 (2012), and checked according to the Euro code, EC8 (2004). ETABS software was used to conduct pushover analysis before and after applying different-sized openings. The ground-opening effect has also been studied. The results show that by increasing the opening area, the R-factor was reduced. It is more influenced by the opening height than the width, though. By increasing the number of stories, the reduction percentage in the R-Factor increased for openings that are less than 30% of the wall area. The R-factor increases slightly when half of the reinforcement bars are added. Doi: 10.28991/CEJ-2022-08-04-013 Full Text: PDF
14
Silwal, Prabin Kumar, Azadeh Parvin, and Mohannad Alhusban. "Numerical Investigation on Strengthening of Steel Beams for Corrosion Damage or Web Openings Using Carbon Fiber Reinforced Polymer Sheets." Buildings 14, no. 4 (2024): 1069. http://dx.doi.org/10.3390/buildings14041069.
Full textAbstract:
Fiber-reinforced polymers (FRPs) have been widely used to strengthen steel structures, which could suffer from corrosion or the introduction of web openings, for utilities such as ductwork, plumbing, electrical conduits, and HVAC systems. The present numerical study involves the application of unidirectional carbon FRP (CFRP) sheets to steel I-beams, damaged due to corrosion or web openings, to regain their lost load-carrying capacity. Finite element analysis (FEA) was utilized to develop and validate three beam models against existing experimentally tested specimens. Subsequently, a parametric study was conducted investigating the effect of various corrosion levels and the number of circular web openings on the yield and ultimate load capacities of the beams. The optimum number of CFRP layers needed to strengthen corroded beams was determined and six CFRP strengthening scenarios were adopted to determine the best configurations to retrofit steel beams with openings (SBWOs). The results revealed that corrosion, introduced by thinning the bottom flange, reduced both yield and ultimate load capacities, with a nearly perfect linear reduction in ultimate load for each 2.5% thickness loss. The optimum number of CFRP layers depended on the level of corrosion damage. Furthermore, while maintaining a constant total opening area, beams with a greater number of smaller circular web openings demonstrated higher yield and ultimate load capacities than those with fewer larger openings. Out of the six adopted CFRP strengthening scenarios, three configurations that involved applying CFRP sheets to both flanges and the web effectively restored the strength of SBWOs, when adequate CFRP layers were used.
15
Epstein, M. "Buoyancy-Driven Exchange Flow Through Small Openings in Horizontal Partitions." Journal of Heat Transfer 110, no. 4a (1988): 885–93. http://dx.doi.org/10.1115/1.3250589.
Full textAbstract:
This paper describes an experimental study of the phenomenon of buoyancy-driven exchange (countercurrent) flow through openings in a horizontal partition. A density-driven exchange flow was obtained by using brine above the partition and fresh water below the partition. In the first part of the study, flow measurements were made with a single opening, for opening ratios L/D in the range 0.01 to 10.0, where L and D are the length of the opening (in the direction normal to the partition) and the diameter of the opening, respectively. Four different flow regimes are identified as L/D is increased through this range. As a result of the competition between two of these regimes, the exchange flow rate versus L/D relation exhibits a peak. The exchange flow rate was found, for all practical purposes, to be independent of viscosity, enabling a universal correlation between Froude number (dimensionless exchange flow rate) and L/D. The second part of the study was an experimental investigation of the same phenomenon, but with two openings in the horizontal partition. Two openings were observed to give rise to three different flow configurations involving both one-way and countercurrent flows within the openings.
16
Yooprasertchai, Ekkachai, Yonlada Tiawilai, Theerawee Wittayawanitchai, Jiranuwat Angsumalee, Panuwat Joyklad, and Qudeer Hussain. "Effect of Shape, Number, and Location of Openings on Punching Shear Capacity of Flat Slabs." Buildings 11, no. 10 (2021): 484. http://dx.doi.org/10.3390/buildings11100484.
Full textAbstract:
Experimental evidence have proved that punching shear capacity of flat slabs deteriorate with the presence of openings located within the critical perimeter around columns. It is understood that this deterioration varies inversely with the distance of openings from column’s face. However, effect of the shape of openings on punching shear capacity is not well known. This study presents experimental results of 14 flat specimens to investigate the effects of the number (2 and 4), shape (circular, square, and rectangular), and location (1 and 4 times of slab’s thickness from column’s face) of openings on punching shear strength. It was found that circular openings had least influence on punching capacity followed by square and rectangular openings, respectively. Further, placing openings at a distance of four times the slab’s thickness from column’s face had minimal impact on punching capacity. Further, increasing the number of openings from 2 to 4 substantially reduced the punching capacity. An effort was made to predict the punching capacities of all specimens using the descriptive equations of ACI 318-19 and Eurocode 2. Mean of the ratio of experimental to analytical results and standard deviation of ACI equations were found to be more accurate than those of Eurocode 2 predictions.
17
Zhao, Wenjuan, Jian Zhang, Wenfu Zhang, Jin Wang, and Ge Wang. "Changes in the Structural Composition and Moisture-Adsorption Properties of Mechanically Rolled Bamboo Fibers." Materials 15, no. 10 (2022): 3463. http://dx.doi.org/10.3390/ma15103463.
Full textAbstract:
The chemical content, mechanical capability, and dimensional stability of bamboo fibers (BFs) are all directly related to the hygroscopic behavior, which is crucial for industrial applications. To support the utilization of BFs, the structural and chemical composition of BFs with different opening times after mechanical rolling were investigated in this study, and the Guggenheim–Anderson–de Boer (GAB) model was selected to predict their moisture-adsorption properties. The results showed that the length and diameter of the fibers gradually decreased with the increase in the number of openings, and the fibers gradually separated from bundles into single fibers. It was also observed that the treated BFs exhibited different equilibrium moisture contents (EMCs). BFs with a smaller number of openings had a higher hemicellulose content and more exposed parenchyma cells on the fibers, which increased the number of water adsorption sites. As the number of openings increased, the parenchyma cells on the fibers decreased, and the lignin content increased, which reduced the number of fiber moisture-adsorption sites and decreased the EMC of the fibers.
18
Amol, J. Mehetre, B. Kandekar Sachin, and U. Mate Nilesh. "Effect of Horizontal Distance of Web Opening on the Ultimate Load Carrying Capacity of Castellated Steel Beams by an Analytical Approach." Indian Journal of Science and Technology 17, no. 18 (2024): 1889–97. https://doi.org/10.17485/IJST/v17i18.495.
Full textAbstract:
Abstract <strong>Objectives:</strong> The primary objective of this current research is to determine the ideal horizontal spacing for hexagonal web openings and their maximum load-bearing capacity through Finite Element Analysis (FEA). <strong>Methods:</strong> The ISMB150 was implemented as a cross-sectional profile to fabricate distinct models of castellated beams with heights of 225 mm. The height of the web openings remained constant at 150 mm for the castellated beam model. The entire analysis is being done on ANSYS 19.2. <strong>Findings:</strong> The analysis has revealed that, for castellated beams with shallower depths, an optimal horizontal spacing of 44.9 mm for the web openings yields an ultimate load-bearing capacity of 144.26 KN. The results of castellated beams are measured in terms of ultimate load-carrying capacity, span-to-deflection ratio, load density, failure location, span-to-beam depth ratio, and the ratio of horizontal distance of opening-to-opening depth. <strong>Novelty:</strong> This research contributes analytical findings for the ideal horizontal distance of hexagonal web opening through maximum load-bearing capacity. Castellated beams have gained immense popularity within the structural engineering community today due to their visually appealing design featuring a variety of web-opening shapes. The primary objective of this current research is to determine the ideal horizontal spacing for hexagonal web openings and their maximum load-bearing capacity through Finite Element Analysis (FEA). The ISMB150 was implemented as a cross-sectional profile to fabricate distinct models of castellated beams with heights of 225 mm. The height of the web openings remained constant at 150 mm for the castellated beam model. The analysis has revealed that, for castellated beams with shallower depths, an optimal horizontal spacing of 44.9 mm for the web openings yields an ultimate load-bearing capacity of 144.26 KN. The results of castellated beams are measured in terms of ultimate load-carrying capacity, span-to-deflection ratio, load density, failure location, span-to-beam depth ratio, and the ratio of horizontal distance of opening-to-opening depth. This research contributes valuable insights into optimizing the design of castellated beams for enhanced structural performance. Further exploration and validation could provide additional refinements and applications in structural engineering. <strong>Keywords:</strong> Horizontal distance of web opening, Number of openings, Ultimate load carrying capacity, Failure modes, ANSYS, Castellated beams
19
Oukaili, Nazar Kamel, and Abeer Hussein Al-Shammari. "Finite Element Analysis of Reinforced Concrete T-Beams with Multiple Web Openings under Impact Loading." Journal of Engineering 20, no. 06 (2023): 15–27. http://dx.doi.org/10.31026/j.eng.2014.06.02.
Full textAbstract:
In this study, a three-dimensional finite element analysis using ANSYS 12.1 program had been employed to simulate simply supported reinforced concrete (RC) T-beams with multiple web circular openings subjected to an impact loading. Three design parameters were considered, including size, location and number of the web openings. Twelve models of simply supported RC T-beams were subjected to one point of transient (impact) loading at mid span. Beams were simulated and analysis results were obtained in terms of mid span deflection-time histories and compared with the results of the solid reference one. The maximum mid span deflection is an important index for evaluating damage levels of the RC beams subjected to impact loading. Three experimental T-beams were considered in this study for calibration of the program. All models had an identical cross-section and span similar to those of the experimental beams. The diameter of the openings of the experimental beams was 110 mm. Three other diameters were varied (50, 80 and 130) mm. The location of the face of the opening with respect to the location of impact loading was investigated (the face of the opening at distance varied 0d, 0.5d, 1d and 1.5d from the location of loading, where d is the effective depth) and the number of web openings was varied (2,4 and 6) openings. All modeled beams subjected to dropping mass of 24.5 kg with height of drop of 250 mm (as for the experimental beams). Results obtained from this study showed that the behavior of beams with circular openings of diameter equal to 22% the web depth has a small effect on the response of the RC T-beams. On the other hand, introducing circular openings with a diameter equal to 35% and 57% of the web depth (80 and 130 mm) increases the maximum mid span deflection by 23% and 43% respectively. Results also showed that, openings with a distance greater than or equal to 1.5 d from the location of impact loading have no effect on the deflection of the RC beams.
20
Gunawan, Iwan, and Zainal Arifin. "Impeller design for centrifugal pump with number of 5 blades driven four stroke 40 cc petrol engine." KOLECER Scientific Journal of Mechanical Engineering 1, no. 1 (2025): 53–59. https://doi.org/10.23969/ksjme1120252372553-59.
Full textAbstract:
An impeller with five blades was designed to enhance water discharge from the volute. The increased number of blades was expected to exert a more potent force on the water due to a larger surface area. However, excessive blade numbers could obstruct inlet water flow, reducing discharge efficiency. Therefore, a restriction was applied to optimize the blade count. The impeller was developed using an experimental approach, as most designs typically feature four to seven blades. Performance tests were conducted by varying the outlet pipe width through different valve openings, and the effects on water discharge and velocity were analyzed. The results indicated that increasing the rotational speed (rpm) led to a higher discharge rate. At 5,702 rpm with a 100% valve opening, the maximum discharge of 1.426 L/s was achieved, while at 3,536 rpm with a 25% valve opening, the lowest discharge of 0.18 L/s was recorded. The velocity analysis showed that the highest speed of 14.17 m/s occurred at 5,702 rpm with a 25% valve opening, whereas the lowest speed of 2.74 m/s was observed at 3,536 rpm with a fully open valve. These findings confirm that increased valve openings enhance discharge and reduce water velocity due to outlet pipe diameter variations. .
21
Afzal, Nasrin, W. Jonathan Lederer, and M. Saleet Jafri. "Mitochondrial Permeability Transition Pore and Number of Openings." Biophysical Journal 112, no. 3 (2017): 440a. http://dx.doi.org/10.1016/j.bpj.2016.11.2350.
Full text
22
Mehetre, Amol J., Sachin B. Kandekar, and Nilesh U. Mate. "Effect of Horizontal Distance of Web Opening on the Ultimate Load Carrying Capacity of Castellated Steel Beams by an Analytical Approach." Indian Journal Of Science And Technology 17, no. 18 (2024): 1889–97. http://dx.doi.org/10.17485/ijst/v17i18.495.
Full textAbstract:
Objectives: The primary objective of this current research is to determine the ideal horizontal spacing for hexagonal web openings and their maximum load-bearing capacity through Finite Element Analysis (FEA). Methods: The ISMB150 was implemented as a cross-sectional profile to fabricate distinct models of castellated beams with heights of 225 mm. The height of the web openings remained constant at 150 mm for the castellated beam model. The entire analysis is being done on ANSYS 19.2. Findings: The analysis has revealed that, for castellated beams with shallower depths, an optimal horizontal spacing of 44.9 mm for the web openings yields an ultimate load-bearing capacity of 144.26 KN. The results of castellated beams are measured in terms of ultimate load-carrying capacity, span-to-deflection ratio, load density, failure location, span-to-beam depth ratio, and the ratio of horizontal distance of opening-to-opening depth. Novelty: This research contributes analytical findings for the ideal horizontal distance of hexagonal web opening through maximum load-bearing capacity. Castellated beams have gained immense popularity within the structural engineering community today due to their visually appealing design featuring a variety of web-opening shapes. The primary objective of this current research is to determine the ideal horizontal spacing for hexagonal web openings and their maximum load-bearing capacity through Finite Element Analysis (FEA). The ISMB150 was implemented as a cross-sectional profile to fabricate distinct models of castellated beams with heights of 225 mm. The height of the web openings remained constant at 150 mm for the castellated beam model. The analysis has revealed that, for castellated beams with shallower depths, an optimal horizontal spacing of 44.9 mm for the web openings yields an ultimate load-bearing capacity of 144.26 KN. The results of castellated beams are measured in terms of ultimate load-carrying capacity, span-to-deflection ratio, load density, failure location, span-to-beam depth ratio, and the ratio of horizontal distance of opening-to-opening depth. This research contributes valuable insights into optimizing the design of castellated beams for enhanced structural performance. Further exploration and validation could provide additional refinements and applications in structural engineering. Keywords: Horizontal distance of web opening, Number of openings, Ultimate load carrying capacity, Failure modes, ANSYS, Castellated beams
23
Hamid, N. A. A., N. Salleh, N. Ali, et al. "Strengthening RC beams with circular post-opening in shear zone by externally bonded CFRP." IOP Conference Series: Earth and Environmental Science 1347, no. 1 (2024): 012073. http://dx.doi.org/10.1088/1755-1315/1347/1/012073.
Full textAbstract:
Abstract An installation of post-drilled openings in existing reinforced concrete (RC) beams may result in an abrupt change in the beam’s cross-sectional dimensions, which could reduce the beam’s capacity and integrity of the beam. A variety of methods have been developed to adequately reinforce the area around the opening. This study investigates the efficacy of Carbon Fibre Reinforced Polymer (CFRP) sheets for strengthening RC beams with circular post-opening at shear zones. A total of five beams measuring 150 mm width, 300 mm depth and 1550 mm length were casted and tested under four-point load until failure. The beams were consisted of one solid beam used as a control beam, two beams having 100 mm diameter circular openings and another two beams were strengthened using externally bonded CFRP sheets around the openings. The ultimate load capacities, deflections, strain distributions, cracking propagation and failure modes of the tested beams were measured and compared. According to the test results, beams with openings had lower load capacity and less stiffness compared to solid beam. Increasing the number of openings significantly reduced the ultimate load of the beams up to 25%. There are also significant differences between beams without and with strengthening in terms of beam capacity, stiffness and strain distribution.
24
Naqe, Aya W., and Alaa H. Al-zuhairi. "Strengthening of RC Beam with Large Square Opening Using CFRP." Journal of Engineering 26, no. 10 (2020): 123–34. http://dx.doi.org/10.31026/j.eng.2020.10.09.
Full textAbstract:
The use of essential services in modern constructions, such pipes, and ducts, became important, placing these pipes and ducts underneath the soffit of the beam. They made a ceiling sandwich, and that causes to reduce the height of the floor, so the presence of the opening in the beam saves the height of the floor. In this paper, the investigation of the beam response of reinforced concrete simply supported rectangle beams with square web openings is presented, including a number of the web openings (two, four, and eight), in addition to its use in strengthening the member at the openings (when the beam is planned before casting, internal deformation steel bar is used, and in case of the opening is existing in the beam, (CFRP) fabric is used.). The test results indicated that the opening Strengthening of beams might compensate for the decrease of the beam load capacity because of the existence of the openings in the shear zone. The compensation of beam capacity depends on the strengthening method, which was adopted. The shear crack loads of the strengthened with externally CFRP specimen's reduction ranging from (15.38 to 38.46%) of their failure loads while the shear crack load of internally reinforced strengthened ranging from (15.38 to 30.76%).
25
Pierotti, A., M. Leoni, and D. Lo Presti. "NUMERICAL ANALYSES OF UNDERGROUND OPENINGS IN COMPETENT ROCK MASSES: CONTINUOUS VS DISCONTINUOUS." Russian Journal of Construction Science and Technology 5, no. 2 (2019): 5–14. http://dx.doi.org/10.15826/rjcst.2019.2.001.
Full textAbstract:
The paper is aimed at comparing the results of numerical analyses of underground openings in competent rock masses like the Carrara Marble (Italy) by considering a real and well documented case study. More specifically, 3D FEM and DEM analyses were carried out on a rock-mass model interested by two faults and three sets of discontinuities. The geometrical model is representative of deep underground openings where spalling - cracks and rock bursts can occur. PLAXIS 3D and 3DEC were used for the analyses. Intact rock and rock mass characterization of Carrara Marble was inferred from available technical literature. The analysis results were compared in terms of principal stresses and displacements in a number of monitoring points around the opening. The main practical interest is to find out a reliable approach for evaluating the stability of very large openings in a competent rock mass like Carrara marble. For such a purpose, a number of available in-situ stress measurements were used.
26
Gilvaee, Majid Yaseri, and Massood Mofid. "Experimental/Numerical Evaluation of Steel Trapezoidal Corrugated Infill Panels with an Opening." Applied Sciences 11, no. 7 (2021): 3275. http://dx.doi.org/10.3390/app11073275.
Full textAbstract:
This paper investigates the influence of an opening in the infill steel plate on the behavior of steel trapezoidal corrugated infill panels. Two specimens of steel trapezoidal corrugated shear walls were constructed and tested under cyclic loading. One specimen had a single rectangular opening, while the other one had two rectangular openings. In addition, the percentage of opening in both specimens was 18%. The initial stiffness, ultimate strength, ductility ratio and energy dissipation capacity of the two tested specimens are compared to a specimen without opening. The experimental results indicate that the existence of an opening has the greatest effect on the initial stiffness of the corrugated steel infill panels. In addition, the experimental results reveal that the structural performance of the specimen with two openings is improved in some areas compared to the specimen with one opening. To that end, the energy dissipation capacity of the specimen with two openings is obtained larger than the specimen with one opening. Furthermore, a number of numerical analyses were performed. The numerical results show that with increasing the thickness of the infill plate or using stiffeners around the opening, the ultimate strength of a corrugated steel infill panel with an opening can be equal to or even more than the ultimate strength of that panel without an opening.
27
Muthukumar, G., and Manoj Kumar. "Influence of Opening Locations on the Structural Response of Shear Wall." Journal of Nonlinear Dynamics 2014 (November 25, 2014): 1–18. http://dx.doi.org/10.1155/2014/858510.
Full textAbstract:
Shear walls have been conferred as a major lateral load resisting element in a building in any seismic prone zone. It is essential to determine behavior of shear wall in the preelastic and postelastic stage. Shear walls may be provided with openings due to functional requirement of the building. The size and location of opening may play a significant role in the response of shear walls. Though it is a well known fact that size of openings affects the structural response of shear walls significantly, there is no clear consensus on the behavior of shear walls under different opening locations. The present study aims to study the dynamic behavior of shear walls under various opening locations using nonlinear finite element analysis using degenerated shell element with assumed strain approach. Only material nonlinearity has been considered using plasticity approach. A five-parameter Willam-Warnke failure criterion is considered to define the yielding/crushing of the concrete with tensile cutoff. The time history responses have been plotted for all opening cases with and without ductile detailing. The analysis has been done for different damping ratios. It has been observed that the large number of small openings resulted in better displacement response.
28
Jung, Jinman, Taesik Kim, Hong Min, Seongmin Kim, and Young-Hoon Jung. "Intricacies of Opening Geometry Detection in Terrestrial Laser Scanning: An Analysis Using Point Cloud Data from BLK360." Remote Sensing 16, no. 5 (2024): 759. http://dx.doi.org/10.3390/rs16050759.
Full textAbstract:
This study investigates the use of terrestrial laser scanning (TLS) in urban excavation sites, focusing on enhancing ground deformation detection by precisely identifying opening geometries, such as gaps between pavement blocks. The accuracy of TLS data, affected by equipment specifications, environmental conditions, and scanning geometry, is closely examined, especially with regard to the detection of openings between blocks. The experimental setup, employing the BLK360 scanner, aimed to mimic real-world paving situations with varied opening widths, allowing an in-depth analysis of how factors related to scan geometry, such as incidence angles and opening orientations, influence detection capabilities. Our examination of various factors and detection levels reveals the importance of the opening width and orientation in identifying block openings. We discovered the crucial role of the opening width, where larger openings facilitate detection in 2D cross-sections. The overall density of the point cloud was more significant than localized variations. Among geometric factors, the orientation of the local object geometry was more impactful than the incidence angle. Increasing the number of laser beam points within an opening did not necessarily improve detection, but beams crossing the secondary edge were vital. Our findings highlight that larger openings and greater overall point cloud densities markedly improve detection levels, whereas the orientation of local geometry is more critical than the incidence angle. The study also discusses the limitations of using a single BLK360 scanner and the subtle effects of scanning geometry on data accuracy, providing a thorough understanding of the factors that influence TLS data accuracy and reliability in monitoring urban excavations.
29
Musa, Kabiru A., Badorul Hisham Abu Bakar, and Ufuoma Joseph Udi. "Influence of Opening and Boundary Conditions on the Behavior of Concrete Hollow Block Walls: Experimental Results." Journal of Engineering and Technological Sciences 55, no. 5 (2023): 569–76. http://dx.doi.org/10.5614/j.eng.technol.sci.2023.55.5.6.
Full textAbstract:
The assembled pattern of concrete hollow building blocks contributes to the wall structure’s durability. This paper presents experimental research on the behavior of concrete hollow block walls. The experimental work included testing four concrete hollow block wall panels with different opening sizes. Constant vertical axial load was applied on top of the wall panels until failure, characterized by boundary conditions. The results showed that the presence of openings reduced the strength of the wall panels; it was possible to observe these differences since the opening area was between 20 and 40% of the gross wall panel area. It was also observed that while the opening percentage had a significant impact on the strength of the wall, the boundary conditions had a less substantial impact on the overall wall response. A high localized concentration of stress was observed at the top corners of the wall panels and a high stress concentration was also observed along the vertical sides of the openings. Variation in the number and the shape of the openings often changed the failure mechanism in the wall panels, even when the percentage area of the opening remained constant. The wall panels A1-B2 reached peak stress levels at 0.019 MPa, 0.036 MPa, 0.056 MPa, and 0.030 MPa. The equivalent peak strains were 0.018, 0.011, 0.012, and 0.010 respectively. This research established significant data and is expected to help in the design and analysis of axially loaded unreinforced masonry walls with openings.
30
Al-Yacouby, Ahmad Mahamad, Arwie Amri Mazli, M. S. Liew, R. M. Chandima Ratnayake, and Samindi M. K. Samarakoon. "Finite Element Analysis of Steel Plates with Rectangular Openings Subjected to Axial Stress." Materials 15, no. 13 (2022): 4421. http://dx.doi.org/10.3390/ma15134421.
Full textAbstract:
Steel plates with openings are among the important ship structural components used in the ship’s hull to withstand the hydrostatic forces of the ocean, which cause sagging and hogging moments at the ship’s bottom. The existence of openings on plates can cause structural rupture, stress concentration and a decrease in ultimate strength. This research is aimed at investigating the influence of selected parameters on the ultimate capacity of steel plates with rectangular holes subjected to axial stress, using ANSYS finite element analysis (FEA) under its non-linear static structural programme. The main parameters investigated in this paper are the plate thickness, opening aspect ratio, number of openings, position of openings, and the boundary condition of the plate. The influence of these parameters on the stress of plates and their deformation was evaluated. The comparison of the numerical simulation with the well-established analytical method using the Navier solution and Roark’s Formulas showed a good agreement.
31
Hao, Jinfeng, Fawei Diao, and Mingyang Qu. "Analysis on seismic performance of a new type of stiffening rib angle steel damper." E3S Web of Conferences 618 (2025): 02003. https://doi.org/10.1051/e3sconf/202561802003.
Full textAbstract:
This paper proposes a stiffening angle steel damper for beam-column joints. The ABAQUS software is used to study the influence of the thickness, opening ratio and number of openings of the stiffening rib on the energy dissipation performance of the damper. A total of 7 models are set up. Through the reciprocating displacement loading method, the energy dissipation capacity is evaluated by analyzing the damper's hysteretic curves, stress distribution, skeleton curves, and key mechanical parameters under different conditions. The study shows that: Under normal circumstances, it is not advisable to use too thick stiffening ribs, but in areas prone to strong earthquakes, the thickness of the stiffening ribs can be appropriately increased or the opening ratio of the stiffening ribs can be reduced to enhance its energy consumption capacity; at the identical open-hole ratio of the stiffening ribs, as the number of openings increases, the distribution of its energy consumption is more uniform.
32
Rahim, Nurul Izzati, Bashar S. Mohammed, Amin Al-Fakih, et al. "Strengthening the Structural Behavior of Web Openings in RC Deep Beam Using CFRP." Materials 13, no. 12 (2020): 2804. http://dx.doi.org/10.3390/ma13122804.
Full textAbstract:
Deep beams are more susceptible to shear failure, and therefore reparation is a crucial for structural reinforcements. Shear failure is structural concrete failure in nature. It generally occurs without warning; however, it is acceptable for the beam to fail in bending but not in shear. The experimental study presented the structural behavior of the deep beams of reinforced concrete (RC) that reinforces the web openings with externally connected carbon fiber reinforced polymer (CFRP) composite in the shear zone. The structural behavior includes a failure mode, and cracking pattern, load deflection responses, stress concentration and the reinforcement factor were investigated. A total of nine reinforced concrete deep beams with openings strengthened with CFRP and one control beam without an opening have been cast and tested under static four-point bending load till failure. The experimental results showed that the increase the size of the opening causes an increase in the shear strength reduction by up to 30%. Therefore, the larger the openings, the lower the capability of load carriage, in addition to an increase in the number of CFRP layers that could enhance the load carrying capacity. Consequently, utilization of the CFRP layer wrapping technique strengthened the shear behavior of the reinforced concrete deep beams from about 10% to 40%. It was concluded that the most effective number of CFRP layers for the deep beam with opening sizes of 150 mm and 200 mm were two layers and three layers, respectively.
33
Aminitabar, Meysam, Omar Kanaani, and Amir Reza Eskenati. "Numerical Evaluation of the Opening Effects on the Reinforced Concrete Slab Structural Performance." Shock and Vibration 2021 (October 18, 2021): 1–16. http://dx.doi.org/10.1155/2021/1060841.
Full textAbstract:
A finite element method was used in this study to investigate the effects of openings on the resistive behavior of concrete slabs. The presented modeling procedure is used to conduct numerical analyses on the response of reinforced concrete slab subjected to in-plane monotonic loads in X (perpendicular to the beam) and Z (parallel to the beam) directions. Initially, the developed numerical model was calibrated and compared with laboratory results. In building this three-dimensional model, it is attempted to accurately model all nonlinear properties of steel and concrete materials as well as the interactions between them. Then, the behavior of bilaterally concrete slabs under different loads was investigated and used as a reference. Finally, the effect of openings under different loads on the strength of concrete slabs was studied. The results confirm that openings have a great influence on the change of hardness, ductility, initiation and cracking path, and stress distribution under shear and gravitational loading. Moreover, by adding an opening inside the diaphragm, not only did beam and block flooring show more fragile behavior, but also its strength and resistance decreased against lateral load. Given the results of the parametric study of the effect of layout, generally, its place became critical at the state that opening disturbed transmission of shear stresses to the collector beams. By adding the area of the opening and loading in X direction, the concentration of the tensile stresses (equivalent to main maximum stresses) was at the tensile edge as well as at the middle of the flooring around the opening. It is worth noting that an increase in the opening’s area caused the number of tensile stresses to be increased at the middle of the flooring. Meanwhile, the concentration of maximum compressive stresses which is equivalent to the main minimum stresses was at the compressive edge, started at the area of the collectors, and stretched to the edge of the opening. Among different layouts, X-1 and Z-3 states were more critical than other states. Considering openings with different layouts, X-1 and Z-3 have the most stiffness deteriorating and strength in such a way that stiffness deteriorating and strength were 39.93% and 37.89%, respectively, for Z-3 model and 38.68% and 43.33%, respectively, for Z-3 model.
34
Jassim, Nidaa Qassim, and Husain Khalaf Jarallah. "Performance Enhancement of R.C. Beams with Large Web Openings by Using Reactive Powder Composite: An Experimental Study." Al-Nahrain Journal for Engineering Sciences 21, no. 3 (2018): 405–16. http://dx.doi.org/10.29194/njes.21030405.
Full textAbstract:
In this paper an experimental works conducted to study the behavior of R.C. beam with large web opening at different locations and fortified with reactive powder composite (RPC) at the extreme tension zone (bottom edge of opening) and/or extreme compression zone (Top edge of opening). The experimental study is investigate the behavior of twelve beams and study the ability of using normal strength concrete together with RPC in the same section to exploit the advantages of these two materials in optimal way. The main variables are RPC layers locations in tension zone and/or in compression zone and the locations of openings. The ultimate loads, load mid-span deflection behavior and strain for steel and concrete were discussed. The experimental results showed that the ultimate strength was decreased with increasing number of opening about 4% for beams with two openings located in shear zone and 21% for beams with three openings, thus indicating that the stiffness decreases accordingly. The using RPC layers effectively enhanced performance of hybrid beams when compared with using the normal strength concrete layers only. The using RPC layers in compression and tension zones increased the ultimate load about 47 % for beams with two opening located in shear zone, when using RPC in the tension zone and normal strength concrete in the compression zone the ultimate flexural load and ultimate deflection increase little compared with normal concrete.
35
Do, Hoa, Tran Huu Thuy Giang, and Ket Mai. "Vietnamese telephone openings." Language and Dialogue 8, no. 3 (2018): 363–89. http://dx.doi.org/10.1075/ld.00022.do.
Full textAbstract:
Abstract This study builds upon Schegloff’s model as a template to investigate the phenomenon of how Vietnamese people perform their telephone openings. We use a corpus of 50 audio recordings of Vietnamese telephone openings to analyze such a phenomenon through both Conversation Analysis and Ethnography methods in order to capture the data in naturally-occurring settings, and to provide insights into Vietnamese culture that makes Vietnamese telephone openings different from North American ones. The findings demonstrate that Vietnamese telephone openings share some common features with telephone openings in different language communities, especially North American culture. Nevertheless, a number of variations, due to language and cultural differences, still exist. We discuss both theoretical and practical implications.
36
Yuan, Anqi, Dongxu Wang, Yuejiao Jiang, Yifeng Wang, and Jinsong Gui. "Numerical Investigation of the Hydrodynamic Characteristics of a Novel Bucket-Shaped Permeable Breakwater Using OpenFOAM." Journal of Marine Science and Engineering 12, no. 9 (2024): 1574. http://dx.doi.org/10.3390/jmse12091574.
Full textAbstract:
To align with contemporary concepts of low-carbon and environmental protection, a new type of bucket-shaped permeable breakwater, based on the prototype of the bucket-based breakwater in Xuwei Port Area, Lianyungang, Jiangsu Province, China, was proposed. A three-dimensional numerical wave flume was constructed using the OpenFOAM platform and DXFlow (an open-source computational fluid dynamics toolbox based on OpenFOAM). The effectiveness of this numerical wave flume was validated through temporal and spatial verification, wave generation validation, and model testing. The study investigated the effects of bucket porosity, opening shapes, number of openings, and the positioning of these openings on the wave-dissipating performance under regular wave conditions. It analyzed the force characteristics near the openings. The results showed that within the relative wavelength range of L/D between 6.7 and 12.7, relative wave height H/d between 0.175 and 0.275, changes in wavelength had a limited impact on the wave-dissipating performance of the bucket-shaped permeable breakwater. The wave-dissipating performance was primarily related to the porosity, with the optimal overall wave-dissipating performance occurring at a bucket porosity of 12%. The shape and number of openings had a minimal relationship with performance. Additionally, the connecting walls of this type of breakwater experienced the most significant wave impact, suggesting that these areas should be reinforced in practical engineering applications.
37
Madenci, Emrah, Yasin Onuralp Özkılıç, Ceyhun Aksoylu, and Alexander Safonov. "The Effects of Eccentric Web Openings on the Compressive Performance of Pultruded GFRP Boxes Wrapped with GFRP and CFRP Sheets." Polymers 14, no. 21 (2022): 4567. http://dx.doi.org/10.3390/polym14214567.
Full textAbstract:
Pultruded fiber-reinforced polymer (PFRP) profiles have started to find widespread use in the structure industry. The position of the web openings on these elements, which are especially exposed to axial pressure force, causes a change in the behavior. In this study, a total of 21 pultruded box profiles were tested under vertical loads and some of them were strengthened with carbon-FRP (CFRP) and glass-FRP (GFRP). The location, number and reinforcement type of the web openings on the profiles were taken into account as parameters. As a result of the axial test, it was understood that when a hole with a certain diameter is to be drilled on the profile, its position and number are very important. The height-centered openings in the middle of the web had the least effect on the reduction in the load-carrying capacity and the stability of the profile. In addition, it has been determined that the web openings away from the center and especially the eccentric opening significantly reduces the load carrying capacity. Furthermore, when double holes were drilled close to each other, a significant decrease in the capacity was observed and strengthening had the least effect on these specimens. It was also determined that the specimens reinforced with carbon FRP contribute more to the load-carrying capacity than GFRP.
38
Bartoletti, Theodore M., Skyler L. Jackman, Norbert Babai, Aaron J. Mercer, Richard H. Kramer, and Wallace B. Thoreson. "Release from the cone ribbon synapse under bright light conditions can be controlled by the opening of only a few Ca2+ channels." Journal of Neurophysiology 106, no. 6 (2011): 2922–35. http://dx.doi.org/10.1152/jn.00634.2011.
Full textAbstract:
Light hyperpolarizes cone photoreceptors, causing synaptic voltage-gated Ca2+ channels to open infrequently. To understand neurotransmission under these conditions, we determined the number of L-type Ca2+ channel openings necessary for vesicle fusion at the cone ribbon synapse. Ca2+ currents ( ICa) were activated in voltage-clamped cones, and excitatory postsynaptic currents (EPSCs) were recorded from horizontal cells in the salamander retina slice preparation. Ca2+ channel number and single-channel current amplitude were calculated by mean-variance analysis of ICa. Two different comparisons—one comparing average numbers of release events to average ICa amplitude and the other involving deconvolution of both EPSCs and simultaneously recorded cone ICa—suggested that fewer than three Ca2+ channel openings accompanied fusion of each vesicle at the peak of release during the first few milliseconds of stimulation. Opening fewer Ca2+ channels did not enhance fusion efficiency, suggesting that few unnecessary channel openings occurred during strong depolarization. We simulated release at the cone synapse, using empirically determined synaptic dimensions, vesicle pool size, Ca2+ dependence of release, Ca2+ channel number, and Ca2+ channel properties. The model replicated observations when a barrier was added to slow Ca2+ diffusion. Consistent with the presence of a diffusion barrier, dialyzing cones with diffusible Ca2+ buffers did not affect release efficiency. The tight clustering of Ca2+ channels, along with a high-Ca2+ affinity release mechanism and diffusion barrier, promotes a linear coupling between Ca2+ influx and vesicle fusion. This may improve detection of small light decrements when cones are hyperpolarized by bright light.
39
Dewandaru, Ardian, Wahyu Setia Budi, and Gagoek Hardiman. "Pengaruh Desain Penghawaan terhadap Kondisi Termal di Gereja Santo Petrus Sambiroto Semarang." ARSITEKTURA 17, no. 2 (2019): 231. http://dx.doi.org/10.20961/arst.v17i2.30676.
Full textAbstract:
<p><em><span lang="EN-US">Saint Peter Church Sambiroto located in the Semarang City which has tropical climate. The building has many openings like doors and bouvenlights. Currently in the east corridor are given tents to accommodate the number of congregations that exist, and on the east side the hallway is paired with banner to protect the east hallway from sun’s heat. The researcher will examine how openings play a role in creating thermal conditions in buildings. This research method uses field measurement techniques in the church regarding dry temperature, relative humidity and air movement in the church at each worship time in the morning and evening and at point where there are openings and not. After doing research, it was found that the temperature in the morning was still in a comfortable condition but at the evening temperature was above comfortable conditions. Even though all measuring points are affected by fan, the point where has opening has low temperature than where has no opening, in the point where has banner have higher temperature than no banner. This proves that openings play a role in flowing air into the building and banners blocking the air to entering lobby and building area from the east side.</span></em></p>
40
Zhu, Junfeng, Donghui Zheng, and Yifan Li. "Failure Dependence Analysis of Shear Walls with Different Openings under Fortification Earthquakes." Mechanical Engineering Research 3, no. 1 (2013): 185. http://dx.doi.org/10.5539/mer.v3n1p185.
Full textAbstract:
It is necessary to study failure dependence problem in order to solve system reliability in the field of Civil Engineering. In this paper, failure dependence of reinforced concrete shear walls with different openings (including the whole shear wall, the shear wall with small opening, the coupled shear wall, the shear wall frame) are studied under fortification earthquakes using Monte Carlo method. The results demonstrate that failure of reinforced concrete shear walls with different openings is neither fully independent nor fully relevant. The number of failure dependent floors is about one-half total floors. The failure dependent floors are concentrated mainly in the upper part.
41
Liu, Xuhui, Dong Li, Xinju Fu, Yong Gao, and Xudong Wang. "MODELING of Rarefied Gas Flows Inside a Micro-Nozzle Based on the DSMC Method Coupled with a Modified Gas–Surface Interaction Model." Energies 16, no. 1 (2023): 505. http://dx.doi.org/10.3390/en16010505.
Full textAbstract:
In this study, we first considered the influence of micro-nozzle wall roughness structure on molecular collision and reflection behavior and established a modified CLL model. The DSMC method was used to simulate and analyze the flow of the micro-nozzle in the cold gas micro-propulsion system, and the deviation of simulation results before and after the improvement of CLL model were compared. Then, the rarefied flow characteristics under a small needle valve opening (less than 1%) were focused on the research, and the particle position, molecular number density, and spatial distribution of internal energy in the micro-nozzle were calculated. The spatial distributions of the flow mechanism in the micro-nozzle under different needle valve openings were compared and analyzed. It was found that when the needle valve opening is lower than 1%, the slip flow and transition flow regions move significantly upstream of the nozzle, the free molecular flow distribution region expands significantly, and the relationship between thrust force and needle valve opening is obviously different from that of medium and large needle valve openings. The effect of nitrogen temperature on the rarefied flow and thrust force is also discussed in this research. The numerical results showed that as gas temperature increases, the molecular internal energy, momentum, and molecular number density near the nozzle exit are enhanced. The thrust at small needle valve openings was significantly affected by the temperature of the working mass. The results of this study will provide key data for the design and development of cold gas micro-thrusters.
42
Deans, Douglas. "Effect of Openings in Ring-Reinforced Shells." Marine Technology and SNAME News 27, no. 01 (1990): 56–64. http://dx.doi.org/10.5957/mt1.1990.27.1.56.
Full textAbstract:
The ring-reinforced shell is a primary structure used in the marine and industrial world. Stress and buckling analysis of such structures is generally based on axisymmetric analysis wherein all openings in the shell are neglected. In real life, such structures have a large number of openings often made in a random manner. In order to design an appropriate reinforcement at such an opening, it is necessary to carry out a detailed local stress analysis. Such an analysis can be made either through the use of part models or by superelements which include the entire structure, as well as the local reinforcement. Zoom analysis using the whole model is expensive and requires knowledge of multilevel super element techniques. Analysis using part models is cheaper and can be equally reliable. This paper investigates the effects of openings on the stress distribution in ring-reinforced shells, such as submarines, using a finite element model. The stress concentration factors (SCF's) in areas adjacent to the opening are determined from this analysis. Using these SCF's, modeling rules for utilization of part models are developed and recommended for use.
43
Lacerda, A. E., and A. M. Brown. "Nonmodal gating of cardiac calcium channels as revealed by dihydropyridines." Journal of General Physiology 93, no. 6 (1989): 1243–73. http://dx.doi.org/10.1085/jgp.93.6.1243.
Full textAbstract:
The hypothesis that dihydropyridine (DHP)-sensitive calcium channels have three distinct modes of gating has been examined. The major prediction is that the relative frequencies among modes depend on DHP concentration while the kinetics within a mode do not. We tested this by studying whole-cell and single-channel calcium currents in neonatal rat and adult guinea pig cardiac myocytes in different concentrations of several DHPs. In the absence of DHPs calcium currents declined with time but the kinetics, which are the focus of this study, were unchanged. Open-time frequency distributions had insignificant numbers of prolonged openings and were well fit by single tau's. Agonist DHP stereoisomers produced concentration-dependent changes in whole-cell tail current tau's. The frequency distribution of single calcium channel current open times became biexponential and the tau's were concentration dependent. The average number of openings per trace of channels with customary open times increased with increases in DHP concentration. Latencies to first opening for the customary openings and for prolonged openings were shorter in the presence of DHPs. A second larger conductance is another important feature of DHP-bound single calcium channels. Thus DHPs not only caused prolonged openings; they produced numerous changes in the kinetics of customary openings and increased channel conductance. It follows that these effects of DHPs do not support the hypothesis of modal gating of calcium channels. The mode model is not the only model excluded by the results; models in which DHPs are allowed to act only or mainly on open states are excluded, as are models in which the effects are restricted to inactivated states. We suggest a different type of model in which cooperative binding of DHPs at two sites produces the essential changes in kinetics and conductance.
44
Oztop, Hakan, Mohammed A. Almeshaal, Lioua Kolsi, Mohammed Rashidi, and Mohamed E. Ali. "Natural Convection and Irreversibility Evaluation in a Cubic Cavity with Partial Opening in Both Top and Bottom Sides." Entropy 21, no. 2 (2019): 116. http://dx.doi.org/10.3390/e21020116.
Full textAbstract:
A numerical study on natural convection in a cubical cavity with partial top and bottom openings is performed in this paper. One of the vertical walls of the cavity has higher temperature than that of the opposite one; the remaining walls are insulated perfectly. Three-dimensional simulations of governing equations have been performed using a finite volume technique. The results are presented for different parameters such as opening length and Rayleigh number. It is observed that heat transfer rate and fluid flow can be controlled via opening ratio size and Rayleigh number.
45
Hartman, L., E. Alessandri, R. Bos, et al. "AB1165 MEDICATION ADHERENCE DATA IN A RANDOMIZED TRIAL: LARGE CHALLENGES TO COME FROM RAW DATA TO A WORKABLE AND RELIABLE DATASET." Annals of the Rheumatic Diseases 79, Suppl 1 (2020): 1873.2–1873. http://dx.doi.org/10.1136/annrheumdis-2020-eular.3638.
Full textAbstract:
Background:Medication adherence in the GLORIA trial, among elderly patients with rheumatoid arthritis, is measured with caps that register openings of the medication bottle. At each study visit, one or two medication bottles with cap (kits) are dispensed, each containing 90 capsules. Multiple steps are needed to come to a workable dataset to describe adherence.Objectives:To describe the steps that are needed to come from raw data to a workable dataset to analyze adherence data that are recorded by electronic caps.Methods:The medication bottle contains a cap with the ability to register cap openings. The raw dataset from the caps consist of an excel file with one opening event per row, recorded as date and time. One cap yields approximately 90 rows. First, the kit numbers were matched to the corresponding patient numbers, that are recorded in another excel file. Instances where two kits were dispensed were recorded with two kit numbers in one cell and need to be copied to two cells with one kit number. Second, the VLOOKUP function was used to combine dates and kit numbers. One row now contains all openings from one kit. Then, the number of days between first opening and each next opening date was calculated. A range of 90 days was made to calculate how many times the bottle was opened on each day of the 90-days period. The results were color-coded to visualize instances of zero, one or ≥two openings on a day.Results:The colored calendar matrix (Figure 1) can now be used to categorize adherence patterns.Conclusion:A monitoring cap seems a simple instrument to measure adherence. However, multiple steps and a lot of time are needed to come to a workable dataset for the study of adherence patterns.Acknowledgments:The GLORIA project is funded by the European Union’s Horizon 2020 research and innovation programme under the topic ‟Personalizing Health and Care’’, grant agreement No 634886.Disclosure of Interests:Linda Hartman: None declared, Elisa Alessandri: None declared, Reinhard Bos: None declared, Daniela Opris-Belinski Speakers bureau: as declared, Marc R Kok Grant/research support from: BMS and Novartis, Consultant of: Novartis and Galapagos, Hanneke Griep-Wentink: None declared, Ruth Klaasen: None declared, Cornelia Allaart: None declared, George Bruyn: None declared, Hennie Raterman Grant/research support from: UCB, Consultant of: Abbvie, Amgen, Bristol-Myers Sqibb, Cellgene and Sanofi Genzyme, Marieke Voshaar Grant/research support from: part of phd research, Speakers bureau: conducting a workshop (Pfizer), Nuno Gomes: None declared, Rui Pinto: None declared, Thomas Klausch: None declared, WIllem Lems Grant/research support from: Pfizer, Consultant of: Lilly, Pfizer, Maarten Boers: None declared
46
Kamikawa, Yohei. "Impact of the active job openings-to-applicants ratio on the number of ambulance dispatches in Japan, 2003-2021: a longitudinal ecological study." BMJ Open 14, no. 11 (2024): e083755. http://dx.doi.org/10.1136/bmjopen-2023-083755.
Full textAbstract:
ObjectiveTo examine the contribution of the active job openings-to-applicants ratio, a macroeconomic indicator, to the number of ambulance dispatches.DesignLongitudinal ecological study.SettingJapan, between January 2003 and December 2021.ParticipantsAll ambulance dispatches.Primary and secondary outcome measuresThe contribution of the active job openings-to-applicants ratio in a month, adjusted by the number of older people, mean temperature and total population, to the number of ambulance dispatches in that specific month was examined and the primary model was compared to the conventional model considering only the older population, mean temperature, and total population.ResultsThere were 108 724 969 ambulance dispatches during this period. The active job openings-to-applicants ratio was significantly associated with the number of ambulance dispatches (the increase rate of monthly ambulance dispatches for 1% rise in the active job openings-to-applicants ratio, 1.00082; 95% CI 1.00052 to 1.00112). Additionally, the primary model effectively demonstrated better fitness to the actual trend than the conventional model (the quasi-likelihood under the independence model criteria were −2 626 817 720 and −2 626 775 185, respectively).ConclusionsThe number of ambulance dispatches was correlated with the active job openings-to-applicants ratio. Macroeconomic perspectives may be needed to address the issue of increasing ambulance dispatches.
47
Rienties, Bart, Dirk Tempelaar, Miriam Pinckaers, Bas Giesbers, and Linda Lichel. "The Diverging Effects of Social Network Sites on Receiving Job Information for Students and Professionals." International Journal of Sociotechnology and Knowledge Development 2, no. 4 (2010): 39–53. http://dx.doi.org/10.4018/jskd.2010100103.
Full textAbstract:
An increasing number of students, professionals, and job-recruiters are using Social Network Sites (SNSs) for sharing information. There has been limited research assessing the role of individuals seeking a job and receiving information about job openings in SNSs. In this regard, do students, non-managers, and managers benefit from job offers when they are a member of SNSs such as Facebook or LinkedIn? How can differences in receiving information about job openings be explained by the strength-of-weak-ties and structural holes theorems? Results of an online survey among 386 respondents indicate that users of SNSs with more contacts are more likely to receive information about job openings than others. Most information about job openings was transmitted via LinkedIn to professionals. Regression analyses indicate that LinkedIn professionals with more links are more likely to receive information about a job opening. In contrast, the structural holes theory is not supported in this setting. The authors argue that Higher education should actively encourage and train students to use LinkedIn to enhance their employability. Finally, new generation graduates’ use of technology for different tasks and with different people than professionals is considered.
48
TRIATMADJA, RADIANTA, and ANY NURHASANAH. "TSUNAMI FORCE ON BUILDINGS WITH OPENINGS AND PROTECTION." Journal of Earthquake and Tsunami 06, no. 04 (2012): 1250024. http://dx.doi.org/10.1142/s1793431112500248.
Full textAbstract:
The force from a tsunami will damage buildings, such as houses, bridges, and many other coastal infrastructures. The impact and drag force of a tsunami depend on the scale and the characteristics of the tsunami as well as the infrastructures' characteristics. This study was conducted using physical modeling to determine the effect of openings and protection on buildings to reduce the effects of a tsunami attack. The openings were symmetrical about the front and rear walls and were oriented in the direction of the tsunami. Barriers with dimensions that were the same width and three times higher than the building and of various lengths were used to simulate protection against a tsunami. The results indicated that the force on the buildings depends on but is not linearly correlated to the opening. The barrier upstream of the building significantly reduced the force depending on its distance to the building and the surge Froude number; however, the openings still play an important role in reducing the force on a protected building. Simple equations for practical use are proposed to calculate the tsunami force on a building with openings with or without protection.
49
Sari, Dursun. "Rock mass response model for circular openings." Canadian Geotechnical Journal 44, no. 7 (2007): 891–904. http://dx.doi.org/10.1139/t07-034.
Full textAbstract:
The main parameters affecting the failure and deformation state of the rock mass around a circular opening are the level of vertical and horizontal in situ stresses, the characteristics of the rock mass, the diameter of the opening, and the support pressure. The influence of all these parameters on the stress-induced final deformations around circular openings was investigated by a finite difference based two-dimensional numerical simulation for both hydrostatic and nonhydrostatic stress field conditions. From the results of the parametric studies, the variation of tunnel strain versus the ratio of uniaxial compressive strength of the rock mass to in situ vertical stress and the ratio of radial support pressure to in situ vertical stress for fair quality and poor quality rock masses was statistically analysed. As a result of the three-dimensional nonlinear regression analysis and surface curve fitting process by means of a large number of models, a best-fit model with the best correlation with these dimensionless parameters was proposed for calculating tunnel strains and ground response curves. Specific charts were created to highlight the influence of parameters on the deformation response of the openings to various support pressures.Key words: numerical modelling, circular openings, ground response curve, finite difference, FLAC.
50
Naidu, S., and T. Putta. "Non-contrast MRI and surgical concordance in fistula-in-ano." General Surgery, no. 1 (May 15, 2025): 26–33. https://doi.org/10.30978/gs-2025-1-26.
Full textAbstract:
Fistula‑in‑ano is an abnormal connection between the anal canal or rectum and the perianal skin, often resulting from infection in the anal glands. While clinical examination provides some insights, MR fistulogram is essential for detailed assessment and reducing recurrence rates after surgery. Objective – to compare and correlate the pre‑operative non‑contrast MR fistulogram findings with surgical findings, focusing on concordance rates for fistula type, craniocaudal extent of tracts, number and clock position of internal and external openings, and presence of complicating features like secondary tracts, supralevator extension, presence and location of abscesses. Materials and methods. We retrospectively analysed 236 patients with fistula‑in‑ano who underwent both MR fistulogram and subsequent surgery within a span of 1 month over one year. MRI scans were reviewed by an experienced radiologist blinded to surgical findings. Parameters assessed included fistula type (Parks, St. James, simple vs. complex), number and clock position of internal and external openings, craniocaudal level of internal openings, puborectalis involvement, secondary tracts, presence of secondary tracts, and location of abscess, if any. Concordance between MRI and surgical findings was evaluated using percentage agreement and weighted kappa coefficients. Results. Our study cohort had a mean age of 41.7 years, with the majority being men (89%) and cryptoglandular etiology (93.6%). Transsphincteric fistula was the most common type (64%). Complex fistulas were seen in 63.6%. Secondary tracts, abscesses, or multiple tracts were seen in 45%, 30.5%, and 11%, respectively. There was almost perfect agreement between MRI and surgical findings in identifying fistula type, clock position of internal and external openings, secondary tracts, and location of abscesses (k=0.98, 0.93, 0.94, 0.88 and 0.98, respectively), substantial agreement for the craniocaudal level of internal opening (k=0.72), and only moderate agreement for the number of internal and external openings (k=0.56 and 0.51, respectively). Conclusions. Non‑contrast MR fistulogram, with its excellent soft tissue resolution, accurately depicts the type of fistula‑in‑ano, localises the internal and external openings, and identifies the presence of any complicating features with almost perfect agreement between MRI and surgical findings.