Journal articles on the topic 'Diaphragm'
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1
Yang, Mu Ye, Rong Liu, Bo Hai Ji, Han Jiang Xu, Ce Chen, and Duan Duan Zhao. "Fatigue Stress Analysis of Diaphragm Cap Hole in Orthotropic Steel Bridge Decks." Applied Mechanics and Materials 204-208 (October 2012): 3265–69. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.3265.
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Influence of diaphragm parameter on stress amplitude and fatigue damage of diaphragm details were investigated based on Tai Zhou Yangtze River Bridge. FEM of steel bridge deck and diaphragm detail were established. Boundary conditions of the diaphragm details FEM were interpolated by sub-model method, and the accurate local stresses of diaphragm details correspond to different lateral distribution of wheels were calculated. Results show the stress amplitude of diaphragm details reach maximum when wheel off-center position is 150mm, and it decreases with the increase of wheel off-center position greatly. The stress amplitude of diaphragm details increase with the increase of the distance of diaphragms, and increasing diaphragm’s thickness can improve fatigue stress of steel bridge deck.
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Roopa, R., P. Navin Karanth, and S. M. Kulkarni. "Design, fabrication and experimental studies of compliant flexure diaphragm for micro pump." International Journal of Engineering & Technology 7, no. 2.21 (April 20, 2018): 66. http://dx.doi.org/10.14419/ijet.v7i2.21.11838.
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This study reports the performance of piezo actuated compliant flexure diaphragm for micropump and MEMS application. To achieve the high performance of diaphragm at the low operating voltage compliant flexure diaphragm design is introduced. Very limited work has done on the diaphragms of micropump. Large numbers of mechanical micropumps have used plane diaphragms. The central deflection of diaphragm plays an important role in defining the micropump performance. The flow rate of mechanical type micropump strongly depends on the central deflection of diaphragm. In this paper compliant flexure diaphragms are designed for micropump to achieve higher deflection at lower operating voltage. Finite element analysis of compliant flexure diaphragm with single layer PVDF (Polyvinylidene fluoride) actuator is simulated in COMSOL. Compliant flexure diaphragms with a different number of flexures are analyzed. The central deflection of compliant flexure diaphragms is measured for driving voltages of 90V to 140V in 10 steps. The deflection of the compliant flexure diaphragm mainly depends on flexure width and length, the number of flexures in the diaphragm, PVDF thickness, diaphragm thickness and driving voltage. Use of compliant flexure diaphragm for micropump will reduce the mass and driving voltage of micropump. An attempt is made to compare the results of compliant flexure diaphragms with plane diaphragms. From the experimental results it is noticed that the compliant flexure diaphragm deflection is twice that of the plane diaphragm at same driving voltage. Deflection of three flexure and four flexure compliant diaphragms is 10.5µm and 11.5µm respectively at 140V.
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Solovev, M., A. Leonhardt, A. Graf, A. Kunke, and V. Kräusel. "Development of geometry variants and forming technology for metal diaphragms to increase the efficiency of diaphragm compressor." IOP Conference Series: Materials Science and Engineering 1284, no. 1 (June 1, 2023): 012009. http://dx.doi.org/10.1088/1757-899x/1284/1/012009.
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Abstract This article outlines the development of an elastically foldable, bistable diaphragm geometry that enables an increase in the compression volume of diaphragm compressors compared to the use of flat diaphragms. Using a Finite Element Model (FEM) in ABAQUS/Standard, several membrane geometries (truncated cone, cone, and dome) were calculated and analyzed with regard to their elastic deformation. Selected geometries were produced using Single Point Incremental Forming (SPIF) and tested by applying full-area pneumatic pressure to determine the diaphragm’s lifetime.
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Li, Jiyang, Lin Liang, Xiaohan Jia, and Xueyuan Peng. "A new generatrix of the cavity profile of a diaphragm compressor." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 228, no. 10 (November 7, 2013): 1754–66. http://dx.doi.org/10.1177/0954406213511077.
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The small flowrate and the diaphragm’s short life are two shortcomings of the diaphragm compressor. This paper presents a new generatrix of the cavity profile of a diaphragm compressor to increase cavity volume and decrease diaphragm's radial stress. To verify the design theory, the radial stresses on the oil side of the diaphragm in the cavities with the new and traditional generatrices were tested, and the experimental radial stresses agreed with the theoretical values. As the most important evaluation criteria of the cavity profile, the volumes of the cavities with different generatrices and the radial stress distribution of the diaphragm within were investigated under various design conditions. The results showed that the volume of the cavity with the new generatrix was about 6.5% larger than that with the traditional generatrix under the same design condition. Otherwise, with the same cavity volume and radius, the maximal radial stress of the diaphragm in the cavity with the new generatrix decreased by 10.3% stably, compared to that in the cavity with a traditional generatrix. Likewise, in the diaphragm’s centric region where the additional stress caused by the discharge holes occurred, the maximal radial stress of the diaphragm in the cavity with the new generatrix decreased about 11.5%.
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Fleischman, Robert B., Kenneth T. Farrow, and Kristin Eastman. "Seismic Performance of Perimeter Lateral-System Structures with Highly Flexible Diaphragms." Earthquake Spectra 18, no. 2 (May 2002): 251–86. http://dx.doi.org/10.1193/1.1490547.
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Building structures are typically designed using the assumption that the floor systems serve as a rigid diaphragm between the vertical elements of the lateral force-resisting system (lateral system). However, perimeter lateral-system structures with long floor spans possess diaphragms that behave quite flexibly. Difficulty can exist in predicting diaphragm force demand in these structures. Thus, current design may provide insufficient strength to maintain elastic diaphragm response. Inelastic diaphragm response exacerbates the effects of diaphragm flexibility. Such response may lead to poor seismic performance, including nonductile diaphragm failure or structural instability due to high drift demands in the gravity system. An analytical study was performed to determine the effect of diaphragm flexibility and strength on the seismic performance of perimeter lateral-system structures with highly flexible diaphragms. Nonlinear transient analyses were performed using ground motions suites corresponding to multiple levels of hazard for high seismic zones. Design recommendations for flexible diaphragms are presented.
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Okubo, Yuhei, Hiro Ota, Kazuki Syoji, and Satomitsu Imai. "A Prototype MEMS Actuator Driven by Magnetic Fluid Enclosed with Polyimide Diaphragms." Key Engineering Materials 523-524 (November 2012): 557–62. http://dx.doi.org/10.4028/www.scientific.net/kem.523-524.557.
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A MEMS actuator using a magnetic fluid enclosed with polyimide (PI) diaphragms is proposed. The actuator produces a large displacement and force thanks to its structure in which a magnetic fluid is confined between two thin-film PI diaphragms (diameter: 5 mm) fabricated on two silicon substrates. The two substrates with diaphragms are glued together by sandwiching a polyester sheet to form a diaphragm unit. The thickness of the diaphragms is 8.5 µm so that they can deflect greatly. The magnetic fluid inserted between the two diaphragms is composed of magnetite and isoparaffin. The diaphragm unit (containing the magnetic fluid) is deflected by applying an external magnetic field to it with a magnet coil. Response times and displacements of the diaphragms were measured when a magnetic field was applied. Under an applied voltage of 10 V, the diaphragm unit could produce displacements of 4 µm at the diaphragm center. Response time to reach 90% of the maximum diaphragm displacement was about 2 s. Under an applied voltage of 80 V, force generated by the diaphragm unit was 0.065N. It is concluded from these experimental results that the proposed actuator is applicable to MEMS devices such as micro pumps and give another example here.
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Nguyen, Taitan, Neal A. Rubinstein, Camasamudram Vijayasarathy, Lawrence C. Rome, Larry R. Kaiser, Joseph B. Shrager, and Sanford Levine. "Effect of chronic obstructive pulmonary disease on calcium pump ATPase expression in human diaphragm." Journal of Applied Physiology 98, no. 6 (June 2005): 2004–10. http://dx.doi.org/10.1152/japplphysiol.00767.2004.
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We have previously demonstrated that human diaphragm remodeling elicited by severe chronic obstructive pulmonary disease (COPD) is characterized by a fast-to-slow myosin heavy chain isoform transformation. To test the hypothesis that COPD-induced diaphragm remodeling also elicits a fast-to-slow isoform shift in the sarcoendoplasmic reticulum Ca2+ ATPase (SERCA), the other major ATPase in skeletal muscle, we obtained intraoperative biopsies of the costal diaphragm from 10 severe COPD patients and 10 control subjects. We then used isoform-specific monoclonal antibodies to characterize diaphragm fibers with respect to the expression of SERCA isoforms. Compared with control diaphragms, COPD diaphragms exhibited a 63% decrease in fibers expressing only fast SERCA (i.e., SERCA1; P < 0.001), a 190% increase in fibers containing both fast and slow SERCA isoforms ( P < 0.01), and a 19% increase ( P < 0.05) in fibers expressing only the slow SERCA isoform (i.e., SERCA2). Additionally, immunoblot experiments carried out on diaphragm homogenates indicated that COPD diaphragms expressed only one-third the SERCA1 content noted in control diaphragms; in contrast, COPD and control diaphragms did not differ with respect to SERCA2 content. The combination of these histological and immunoblot results is consistent with the hypothesis that diaphragm remodeling elicited by severe COPD is characterized by a fast-to-slow SERCA isoform transformation. Moreover, the combination of these SERCA data and our previously reported myosin heavy chain isoform data (Levine S, Nguyen T, Kaiser LR, Rubinstein NA, Maislin G, Gregory C, Rome LC, Dudley GA, Sieck GC, and Shrager JB. Am J Respir Crit Care Med 168: 706–713, 2003) suggests that diaphragm remodeling elicited by severe COPD should decrease ATP utilization by the diaphragm.
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Kim, Yong Hwy, Ji Hoon Phi, Seung-Ki Kim, and Kyu-Chang Wang. "Growth pattern of craniopharyngioma determined by the origin of tumor regarding diaphragma sellae and the competency of the aperture: Reappraisal in the era of endoscopic endonasal surgery." Journal of Korean Skull base society 18, no. 1 (May 31, 2023): 24–35. http://dx.doi.org/10.55911/jksbs.23.0005.
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Background: Advances in the endoscopic endonasal approach (EEA) have increased the under-standing of craniopharyngioma anatomy. We have previously proposed a relationship among cranio-pharyngioma growth pattern, their origin relative to the diaphragm sellae, and their aperture compe-tency. To reappraise that relationship, we retrospectively reviewed the diaphragm sellae anatomy of patients who underwent EEA for craniopharyngioma. Materials and Methods: From May 2010 to January 2013, thirty five patients underwent EEA procedures for craniopharyngiomas. Twenty patients without a surgical history were included in the study, and medical records describing the spatial relations between the tumors and the diaphragma sellae were reviewed and correlated with the tumor growth patterns on preoperative images. Results: All of the tumors were completely removed. Three prechiasmatic tumors were located un-der intact diaphragma sellae. Six retrochiasmatic tumors were composed of supra- and subdiaphrag-matic components that were continuous through an incomplete aperture of the diaphragm. Eleven retrochiasmatic tumors were located above intact diaphragms. Visual symptoms were normalized or improved in twelve of the sixteen patients with preoperative visual deficits. Preoperative hypotha-lamic dysfunction was recovered in ten of twelve patients. Conclusions: The EEA revealed the detailed tumor anatomy and confirmed our previous hypoth-esis that craniopharyngioma growth patterns are principally determined by the origin of the tumor relative to the diaphragma sellae and by the aperture competency. The EEA is indicated for removing both prechiasmatic and retrochiasmatic craniopharyngiomas.
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Farkas, G. A., and D. F. Rochester. "Functional characteristics of canine costal and crural diaphragm." Journal of Applied Physiology 65, no. 5 (November 1, 1988): 2253–60. http://dx.doi.org/10.1152/jappl.1988.65.5.2253.
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We estimated the in situ force-generating capacity of the costal and crural portions of the canine diaphragm by relating in vitro contractile properties and diaphragmatic dimensions to in situ lengths. Piezoelectric crystals were implanted on right costal and left crural diaphragms of anesthetized dogs, via midline laparatomy. With the abdomen reclosed, diaphragm lengths were recorded at five lung volumes. Contractile properties of excised muscle bundles were then measured. In vitro force-frequency and length-tension characteristics of the costal and crural diaphragms were virtually identical; their optimal force values were 2.15 and 2.22 kg/cm2, respectively. In situ, at residual volume, functional residual capacity (FRC), and total lung capacity the costal diaphragm lay at 102, 95, and 60% of optimal length (Lo), whereas the crural diaphragm lay at 88, 84, and 66% of Lo. Muscle cross-sectional area was 40% greater in costal than in crural diaphragms. Considering in situ lengths, cross-sectional areas, and in vitro length-tension characteristics at FRC, the costal diaphragm could exert 60% more force than the crural diaphragm.
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Filiatrault, Andre, David Fischer, Bryan Folz, and Chia-Ming Uang. "Experimental parametric study on the in-plane stiffness of wood diaphragms." Canadian Journal of Civil Engineering 29, no. 4 (August 1, 2002): 554–66. http://dx.doi.org/10.1139/l02-036.
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This paper presents the results of in situ quasi-static tests on a full-scale wood floor diaphragm in a two-storey woodframe house. The main objective of the study was to investigate the in-plane flexibility/rigidity of the diaphragm. Fourteen different diaphragm and structural configurations were investigated. The main parameters considered in the study included the nail schedule, panel-edge blocking, sub-floor adhesive, perpendicular walls above and below the diaphragm, and wall finish materials. The results indicated that panel-edge blocking increased significantly the diaphragm shear stiffness, particularly for diaphragms without sub-floor adhesive. Also, the presence of perpendicular walls acting as additional chord members caused a significant increase in the flexural stiffness of the diaphragm. The design procedure included in the Uniform Building Code (UBC) to compute in-plane diaphragm deformations was assessed by comparing its predictions with the experimental results. The UBC predictions agreed well with the experimental results for some configurations, but the correlation was poor for others.Key words: diaphragms, floor, tests, wood, wooden structures.
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Tomić, Igor, Francesco Vanin, Ivana Božulić, and Katrin Beyer. "Numerical Simulation of Unreinforced Masonry Buildings with Timber Diaphragms." Buildings 11, no. 5 (May 14, 2021): 205. http://dx.doi.org/10.3390/buildings11050205.
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Though flexible diaphragms play a role in the seismic behaviour of unreinforced masonry buildings, the effect of the connections between floors and walls is rarely discussed or explicitly modelled when simulating the response of such buildings. These flexible diaphragms are most commonly timber floors made of planks and beams, which are supported on recesses in the masonry walls and can slide when the friction resistance is reached. Using equivalent frame models, we capture the effects of both the diaphragm stiffness and the finite strength of wall-to-diaphragm connections on the seismic behaviour of unreinforced masonry buildings. To do this, we use a newly developed macro-element able to simulate both in-plane and out-of-plane behaviour of the masonry walls and non-linear springs to simulate wall-to-wall and wall-to-diaphragm connections. As an unretrofitted case study, we model a building on a shake table, which developed large in-plane and out-of-plane displacements. We then simulate three retrofit interventions: Retrofitted diaphragms, connections, and diaphragms and connections. We show that strengthening the diaphragm alone is ineffective when the friction capacity of the wall-to-diaphragm connection is exceeded. This also means that modelling an unstrengthened wall-to-diaphragm connection as having infinite stiffness and strength leads to unrealistic box-type behaviour. This is particularly important if the equivalent frame model should capture both global in-plane and local out-of-plane failure modes.
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Johnson, Robert I., and Rebecca A. Atadero. "Simple-Made-Continuous Steel Bridges with Steel Diaphragms." Engineering Journal 54, no. 1 (March 31, 2017): 3–20. http://dx.doi.org/10.62913/engj.v54i1.1111.
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Simple-made-continuous (SMC) bridges are a relatively new innovation in steel bridge design. The majority of SMC bridges currently in use are constructed with concrete diaphragms. This article presents the results of numerical analysis and physical laboratory testing of an alternative simple-made-continuous (SMC) connection scheme that uses steel diaphragms in lieu of concrete diaphragms. A bridge using steel diaphragms was constructed by the Colorado Department of Transportation in 2005, and the connections on this bridge serve as the basis for the research discussed herein. The results of the analysis and testing provided information for the development of a design methodology based on the physical behavior of the SMC connection. The paper also compares the steel-diaphragm SMC connection to concretediaphragm SMC connections and demonstrates that the steel-diaphragm design has several desirable features. For a diaphragm cost, which is similar in cost to other SMC schemes, the steel-diaphragm design requires less total construction time. Additionally, because the girder ends are exposed, it is easy to verify that the girders have fully weathered (for weathering steel), they may be easily inspected, and there is no concern about cracking of a concrete diaphragm at re-entrant corners around the steel bridge girders.
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Suja, K. J., Bhanu Pratap Chaudhary, and Rama Komaragiri. "Design and Simulation of Pressure Sensor for Ocean Depth Measurements." Applied Mechanics and Materials 313-314 (March 2013): 666–70. http://dx.doi.org/10.4028/www.scientific.net/amm.313-314.666.
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MEMS (Micro Electro Mechanical System) are usually defined as highly miniaturized devices combining both electrical and mechanical components that are fabricated using integrated circuit batch processing techniques. Pressure sensors are usually manufactured using square or circular diaphragms of constant thickness in the order of few microns. In this work, a comparison between circular diaphragm and square diaphragm indicates that square diaphragm has better perspectives. A new method for designing diaphragm of the Piezoresistive pressure sensor for linearity over a wide pressure range (approximately double) is designed, simulated and compared with existing single diaphragm design with respect to diaphragm deflection and sensor output voltage.
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Eivani, Hamed, Abdolreza S. Moghadam, Armin Aziminejad, and Masoud Nekooei. "Seismic Response of Plan-Asymmetric Structures with Diaphragm Flexibility." Shock and Vibration 2018 (2018): 1–18. http://dx.doi.org/10.1155/2018/4149212.
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The seismic behavior of asymmetric structures with a flexible diaphragm was studied by conducting inelastic dynamic time-history analyses. Asymmetric structures with different configurations of mass, stiffness, and strength centers, in combination with a wide range of diaphragm flexibility, were evaluated. The behavior of structures was studied by considering three aspects:(1)effect of structural asymmetry on diaphragms deformation;(2)effect of diaphragm flexibility on demands of the lateral load-resisting elements;(3)optimum configuration of mass, stiffness, and strength centers to limit important engineering demand parameters in asymmetric structures with a flexible diaphragm. The results showed that the shear-dominant deformation of diaphragms is sensitive to both structure asymmetry specifications and the degree of diaphragm flexibility; therefore, it can be used for the qualitative classification of the seismic behavior of structures. Also, the center of strength in structures with flexible diaphragm is more important relative to the stiffness center and has a significant effect on engineering demands at all levels of diaphragm flexibility. Moreover, it was found that a suitable configuration of centers in torsionally stiff structures depends on the degree of diaphragm flexibility, in addition to the intensity of earthquakes (structure yield level) and selected engineering demand parameter.
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Bukusi, Elizabeth A., Maria F. Gallo, Anjali Sharma, Betty Njoroge, Denise J. Jamieson, Rosemary Nguti, April J. Bell, and David A. Eschenbach. "Adherence to Diaphragm Use for Infection Prevention: A Prospective Study of Female Sex Workers in Kenya." Infectious Diseases in Obstetrics and Gynecology 2009 (2009): 1–11. http://dx.doi.org/10.1155/2009/420196.
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Objective. To assess adherence to and acceptability of the diaphragm among 140 female sex workers in Kenya in a 6-month prospective study.Methods. At baseline and bimonthly visits, participants were interviewed on diaphragm knowledge, attitude, and practices. We used principal component analysis and logistic regression to identify predictors of consistent use.Results. At 50% of 386 bimonthly visits, women reported consistently using a diaphragm with all partners during the preceding 2 weeks. Consistent use was significantly higher at the 6-month than the 2-month visit. Women reported less covert use with “helping” (regular sex partners to whom she could go for help or support) than with “other” partners. Perceptions that diaphragms are easier to use than condoms and that their lack of coital interruption is important were associated with consistent diaphragm use with both partner types. Partner support of diaphragm use is correlated with consistent use with “helping” partners only while higher parity, consistent condom use, and perceived lack of need of condoms as a benefit of diaphragms were associated with consistent use with “other” partners.Conclusions. Diaphragm acceptance among female sex workers in Nairobi was high. Future studies should distinguish between partner types when evaluating diaphragm adherence.
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Bazzy, A. R. "Effect of hypoxia on neuromuscular transmission in the developing diaphragm." Journal of Applied Physiology 76, no. 2 (February 1, 1994): 708–13. http://dx.doi.org/10.1152/jappl.1994.76.2.708.
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To study the effects of hypoxia on neuromuscular transmission in the developing diaphragm, phrenic nerve-hemidiaphragm preparations were obtained from newborn (4–9 days) and older (22–30 days) rats. Diaphragms were stimulated directly or indirectly (via the nerve) for 1 s at frequencies of 10–80 Hz. Force generated in response to stimulation was measured during perfusion of oxygenated Ringer solution (control) and Ringer solution bubbled with 95% N2–5% CO2 (hypoxia). After 45 min of hypoxia, the force response of the older diaphragms to direct stimulation had decreased to approximately 50% of control at > or = 40 Hz; however, when stimulation occurred via the nerve at these frequencies only 15–20% of control force was generated. In the newborn diaphragms, the force decrement after similar or longer periods of hypoxia (< or = 90 min) was 30– 40% irrespective of the route or frequency of stimulation. After 15 min of reoxygenation, the force response to both muscle and nerve stimulation recovered completely in the older diaphragms but only partially in the newborn diaphragms (range 77% of control at 50 Hz to 95% of control at 10 Hz). These data suggest that in the newborn diaphragm 1) neuromuscular transmission is more resistant to the effects of hypoxia than the older diaphragm and 2) the predominant effect of hypoxia is peripheral in the diaphragm muscle fibers, whereas in the older diaphragm the effect is before or at the neuromuscular junction.
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Margulies, S. S. "Regional variation in canine diaphragm thickness." Journal of Applied Physiology 70, no. 6 (June 1, 1991): 2663–68. http://dx.doi.org/10.1152/jappl.1991.70.6.2663.
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To quantify the relationship between both regional and overall diaphragm morphometry and body weight in the dog, diaphragm thickness was measured in five regions of the costal diaphragm and three regions of the crural diaphragm in 40 healthy dogs (8-40 kg). Surface area of the diaphragm, diaphragm weight, and body weight were also determined. Diaphragm surface area and weight varied linearly with body weight, but there was no significant correlation between overall diaphragm thickness and body weight. Diaphragm thickness varied significantly between regions, and three regions had systematic left-to-right differences as well. Because diaphragm geometry influences the diaphragm's function as a pressure generator, regional differences in thickness may alter the relationship between the force developed by the activation of a particular region of the diaphragm and its action on the respiratory system.
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Liu, Judy. "Steel Structures Research Update: Steel Diaphragm Innovation Initiative." Engineering Journal 56, no. 2 (June 30, 2019): 123–30. http://dx.doi.org/10.62913/engj.v56i2.1149.
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The Steel Diaphragm Innovation Initiative (SDII) is a multiyear academic-industry partnership to advance the seismic performance of steel floor and roof diaphragms in steel buildings is highlighted. The team includes AISC T.R. Higgins Lectureship Award and AISC Milek Fellowship Award winners for topics ranging from developments in long-span composite slabs to buckling-restrained braced frames to continuity plate detailing for steel moment-resisting connections. The team’s motivations for creating SDII stemmed from issues with respect to the knowledge base for steel diaphragm performance, codes and standards, as well as missed opportunities for advancements in seismic performance-based design. The available research on steel diaphragms was primarily focused on the strength of isolated systems; little was known about ductility or whole-building performance. The team developed a five-year case and plan to “advance the seismic performance of steel floor and roof diaphragms utilized in steel buildings through better understanding of diaphragm-structure interaction, new design approaches, and new three-dimensional modeling tools that provide enhanced capabilities to designers utilizing steel diaphragms in their building systems” (SDII, 2017). The work includes providing research support for much-needed revisions to proposed seismic codes and standards for steel diaphragms. SDII is also working on innovative steel diaphragm solutions for efficient, robust and resilient steel building systems.
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Wilson, Aaron, Pierre Quenneville, and Jason Ingham. "Natural Period and Seismic Idealization of Flexible Timber Diaphragms." Earthquake Spectra 29, no. 3 (August 2013): 1003–19. http://dx.doi.org/10.1193/1.4000162.
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The current equations for diaphragm fundamental period determination and for diaphragm deformation determination published in commonly used seismic assessment documents are firstly reviewed to establish their origin. Using a validated analytical model that captures diaphragm deformation mechanics, three beam idealizations (a fixed-ended flexure beam, a pin-ended flexure beam, and a shear beam) are compared against true diaphragm behavior to determine which idealization is most suitable for the seismic assessment of diaphragm performance. Wherever necessary, recommendations have been made to update and to harmonize the current seismic assessment procedures for timber diaphragms in unreinforced masonry buildings. The presented analysis is specifically focused on straight-sheathed timber diaphragm configurations that are typically found in historic unreinforced masonry buildings.
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Tibi, Ariel, Michael Burt, and Elisha Tatsa. "Spatial Stiffening Diaphragm Systems." International Journal of Space Structures 13, no. 1 (March 1998): 23–27. http://dx.doi.org/10.1177/026635119801300103.
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Spatial helicoid diaphragms as stiffening systems in multi-storey buildings can achieve the following advantages: 1. increase resistance to horizontal forces. 2. increase stability against buckling. The development from horizontal diaphragms, which are common these days, through inclined diaphragms, to spatial stiffening diaphragm systems is discussed in the paper. Examples from nature, as shown in the paper provide a basis for further research and development.
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Stan, Radu V. "Multiple PV1 dimers reside in the same stomatal or fenestral diaphragm." American Journal of Physiology-Heart and Circulatory Physiology 286, no. 4 (April 2004): H1347—H1353. http://dx.doi.org/10.1152/ajpheart.00909.2003.
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Several of the endothelium-specific structures that have been involved in microvascular permeability [such as caveolae, transendothelial channels (TECs), vesiculovacuolar organelles (VVOs), and fenestrae] can be provided with either a stomatal or fenestral diaphragm. In the case of fenestrae, the diaphragm has the presumed function of creating a permselective barrier for solutes from blood plasma and interstitium. PV1 is an endothelium-specific integral membrane glycoprotein that is associated with both the stomatal diaphragms of caveolae, TECs, and VVOs as well as the diaphragms of endothelial fenestrae. The intimate structure of these diaphragms has been shown to consist of a meshwork formed by radial fibrils. We have recently shown that PV1 is a key structural element of both types of diaphragms, with its expression being sufficient to form de novo stomatal and fenestral diaphragms in both endothelial and nonendothelial cell types in culture. We have further tested the role of PV1 in the structure of the diaphragms and demonstrate here that multiple PV1 homodimers reside in close proximity within the same diaphragm. Our data bring further support to the paradigm by which PV1 dimers would form the fibrils of the diaphragms with a function in the microvascular permeability.
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Lee, J. H., D. H. Oh, G. J. Lee, S. C. Joo, B. Yang, Sung Jin Kim, and Chang Joo Kim. "Fabrication of Pressure Sensors with Diaphragm by Electro-Chemical Etch-Stop." Materials Science Forum 475-479 (January 2005): 1853–56. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.1853.
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A diaphragm, the most important part of pressure sensor, was successfully fabricated by an electro-chemical etch-stop (ECES) technique. It was important to control the thickness of the diaphragm precisely. We compared characteristic results of diaphragms by electro-chemical etch-stop with those by time-control etch-stop (TCES). The 4 inch n-Epi/p-substrate with 16±1 ㎛ thickness was utilized because the thickness of the diaphragm fabricated by ECES is controlled by the thickness of Epi.. The etching of silicon wafer was carried out in the solution (25 wt% KOH) at 80°C, using 3 electrode system with potentiostat. Proper voltages were applied to etch p/n-type silicon wafer after determined open circuit potential (OCP) and passivation potential (PP) of n and p-type silicon, respectively. Thickness of diaphragms fabricated by ECES was controlled in the range of 16±1 ㎛ while that by TCES was in the range of 16.1±2 ㎛. The roughness of diaphragm was 52±5 Å. When the pressure of 50 kPa was applied on the pressure sensor using the diaphragm fabricated by ECES, the error rate was improved to ±10 ㎷. In the case of the error rate of pressure sensor using the diaphragm fabricated by TC was in the range of ±25 ㎷ under the same condition.
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Goodyear-Bruch, Caryl A., Jay Jegathesan, Richard L. Clancy, and Janet D. Pierce. "Apoptotic-Related Protein Expression in the Diaphragm and the Effect of Dopamine During Inspiratory Resistance Loading." Biological Research For Nursing 9, no. 4 (April 2008): 293–300. http://dx.doi.org/10.1177/1099800408314573.
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Dopamine (DA) is a free radical scavenger that attenuates apoptosis. We studied the effects of normal saline (NS) and DA on diaphragm apoptotic protein expression following 60 min of inspiratory resistance loading in rats. We tested for 27 apoptotic-related proteins and found 12 in the diaphragm. Of the 12 proteins, superoxide dismutase copper zinc (SOD [CuZn]) and proprioceptive event related potential (PERP) were significantly higher in the DA group than in the NS and sham groups ( p = .002, p = .007). DA group diaphragms had significantly greater expression of SOD (CuZn) than the NS ( p = .005) and sham group diaphragms ( p = .003). Likewise, the DA group had significantly greater expression of PERP than the NS group ( p = .008). These results suggest that DA decreases diaphragm apoptosis through elevated expression of SOD (CuZn). The identification of 12 apoptotic-related proteins will assist investigators as they study diaphragm apoptosis.
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V.Mouliraj, Ramesh Kumar Yadav, and N.Balachandar. "Pressure sensor diaphragm modelling and deformation analysis." International Journal of Scientific Methods in Engineering and Management 01, no. 03 (2023): 01–08. http://dx.doi.org/10.58599/ijsmem.2023.1301.
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This paper develops Micro-electromechanical Systems-based pressure sensor diaphragms (MEMS). This paper aims to build, model, and test a MEMS-based diaphragm that uses numerous structures of the same area and material to sense differential pressure. Similar goals: Diaphragm deflection and sensitivity were studied using COMSOL multiphysics software. LTspice is a high-performance SPICE simulator with a graphical schematic capture interface. The diaphragm bends when pressure changes, affecting the substrate-diaphragm displacement in COMSOL and the voltage output in LTspice via changing the resistances of three sensors. Voltage output changes with diaphragm bending. Changing voltage and displacement indicate environmental pressure. This method improves instrument response. In this work, a circular diaphragm-based pressure sensor has higher displacement, sensitivity, and stress output responses than a square or rectangular one.
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Zhao, Kai, Yuan Lou, Guangjie Peng, Chengqiang Liu, and Hao Chang. "A Review of the Development and Research Status of Symmetrical Diaphragm Pumps." Symmetry 15, no. 11 (November 20, 2023): 2091. http://dx.doi.org/10.3390/sym15112091.
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With the continuous improvement in human awareness of environmental protection, energy savings, and emission reduction, as well as the vigorous development of precision machinery and process technology, energy-saving and efficient diaphragm pumps have become a hot research topic at home and abroad. The diaphragm pump is a membrane-isolated reciprocating transport pump that isolates the transport medium from the piston through the diaphragm and can be used to transport high-viscosity, volatile, and corrosive media, and the symmetrical structure can make it easier for the diaphragm pump to achieve stable operation, reduce vibration and noise, and extend the life of the pump. This paper summarizes the development and research status of diaphragm pumps in recent years, including diaphragm pump structure, working principle, category, cavitation research, wear research, fault diagnosis research, vibration and noise research, fluid–solid-interaction research, and optimum research on one-way valves and diaphragms. It also puts forward some reasonable and novel viewpoints, such as applying the theory of entropy production to explore the motion mechanism of diaphragm pumps, optimizing the performance of diaphragm pumps, using new technologies to study new materials for diaphragm pumps, and designing diaphragm protection devices. This review provides valuable references and suggestions for the future development and research of diaphragm pumps.
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Sugiura, T., S. Morita, A. Morimoto, and N. Murakami. "Regional differences in myosin heavy chain isoforms and enzyme activities of the rat diaphragm." Journal of Applied Physiology 73, no. 2 (August 1, 1992): 506–9. http://dx.doi.org/10.1152/jappl.1992.73.2.506.
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Myosin heavy chain isoforms and enzyme activities were compared between the costal and crural regions of the rat diaphragm. The percentage of heavy chain (HC) IIb in the crural region of the diaphragm was significantly (P less than 0.05) higher than that in the costal region (mean 7.3 vs. 3.0%), and the percentage of HCI was significantly lower in the crural than in the costal diaphragm (22.7 vs. 27.9%). The distributions of HCIIa and HCIId were relatively homogeneous in both regions. Succinate dehydrogenase activity in the costal diaphragm was 21% greater (P less than 0.01) than in the crural diaphragm. In contrast, there was no significant difference in the activity of phosphofructokinase in the crural and costal diaphragms. These results demonstrate that a difference in myosin heavy chain isoforms and oxidative capacity exists between the costal and crural regions of the rat diaphragm.
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Angelillo, Maurizio, Aladin M. Boriek, Joseph R. Rodarte, and Theodore A. Wilson. "Shape of the canine diaphragm." Journal of Applied Physiology 89, no. 1 (July 1, 2000): 15–20. http://dx.doi.org/10.1152/jappl.2000.89.1.15.
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In an earlier study (Angelillo M, Boriek AM, Rodarte JR, and Wilson TA. J Appl Physiol83: 1486–1491, 1997), we proposed a mathematical theory for the structure and shape of the diaphragm. Muscle bundles were assumed to lie on lines that are simultaneously geodesics and lines of principal curvature of the diaphragm surface, and the class of surfaces that are formed by line elements that are both geodesics and lines of principal curvature was described. Here we present data on the shape of the canine diaphragm that were obtained by the radiopaque marker technique, and we describe a surface that fits the data and satisfies the requirements of the theory. The costal and crural diaphragms are fit by cyclides with radii of 3.7 and 2.3 cm, respectively. In addition, the theory is extended to include the description of a joint between cyclides, and the observed properties of the joint between the costal and crural diaphragms at the dorsal end of the costal diaphragm match those required by the theory.
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Samad, Nur Jannati. "OBSERVASI DIAPHRAGM WALL METODE CUT OFF WALL SEBAGAI PENANGANAN REMBESAN WILAYAH WADUK CENGKLIK." Jurnal Proyek Teknik Sipil 6, no. 2 (September 6, 2023): 1–11. http://dx.doi.org/10.14710/potensi.2023.16712.
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Cengklik Reservoir is one of the tourist attractions in the Boyolali area. Functionally, the Cengklik reservoir is used as a water reservoir or storage area as well as a source of water for the needs of the surrounding community and to supply rice fields. Based on observations, the reservoir has decreased in function, namely seepage is found. One of the methods applied for the handling of seepage is the foundation structure in the form of a diaphragm wall. Observations were started by collecting data (pumping test data and drawings of the diaphragm wall structure). The results obtained for the total diaphragm wall foundation with a depth of 16 m with a depth of excavated soil of 16 m. Specifications for the diaphragm wall plan with a land area of 375m. Diaphragma wall (slurry wall) is a type of plastic concrete retaining wall with a foundation that has very strong rigidity, low vibration during construction, and has a waterproof function. Diaphragama wall provides less seepage effect than other methods such as secant pile. The secant pile only has the same use but differs in area. Cut off wall is a method of excavation work, surrounded by excavated land such as a guide wall. Insulation or retaining water flow on large dam foundations is usually done by the Cut of wall method. This method is suitable for excavation work which is quite deep and dense soil area
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Saleem Khan, Khurram, James Meaney, Ignacio Martin-Loeches, and Daniel V. Collins. "MRI Assessment of Global and Regional Diaphragmatic Motion in Critically Ill Patients Following Prolonged Ventilator Weaning." Medical Sciences 7, no. 5 (May 22, 2019): 66. http://dx.doi.org/10.3390/medsci7050066.
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Introduction: diaphragmatic dysfunction is a common cause of slow weaning in mechanically ventilated patients. Diaphragmatic dysfunction in ventilated patients can be global or regional. The aim of our study was to evaluate the motion of the entire diaphragm in patients who were ventilated for a protracted period in comparison with healthy controls by using Magnetic Resonance Imaging (MRI). Methods: Intensive care patients who had a prolonged ventilator wean and required tracheostomies were enrolled based on extensive exclusion criteria. MRI dynamic sequence and subtraction images were used to measure vertical displacement at five different points on each hemi-diaphragm during normal tidal breathing. Tidal displacement of each point on the right and left hemi-diaphragms of the patients were compared to the precise respective points on the right and left hemi-diaphragms of enrolled controls. Results: Eight intensive care patients and eight controls were enrolled. There were observed significant differences in the displacements of the left hemi-diaphragm between the two groups (median 6.4 mm [Interquartile range (IQR), 4.6–12.5]) vs. 11.6 mm [IQR, 9.5–14.5], p = 0.02). There were also observed significant differences in the displacements at five evaluated study points on the left hemi-diaphragms of the patients when compared to the precise respective points in controls, especially at the dome (median 6.7 mm [IQR, 5.0–11.4] vs. 13.5 mm [IQR 11.5-18], p value = 0.005) and the anterior zone of apposition (median 5.0 mm [IQR, 3.3–7.1] vs. 7.8mm [IQR, 7.1–10.5], p value = 0.01). The intensive care patients showed lower minimal and maximal values of displacement of right hemi-diaphragms compared to the controls, suggesting that the differences in the displacement of right hemi-diaphragm are possible; however, the differences in the mean values of displacement of right hemi-diaphragm between the intensive care patient group and the control group (median 9.8 mm [IQR (Interquartile range), 5.0–12.3] vs. 10.1 mm [IQR 8.3–18.5], p = 0.12) did not reach the level of significance. Conclusion: Although frequently global, diaphragm dysfunction in ventilated patients after prolonged ventilation can also be regional or focal when assessed by MRI dynamic sequence. The vertical displacement of both right and left hemi-diaphragms at various anatomical locations had different values in both controls, and patients. There were significant focal variations in the movement of diaphragm in patients with ventilator-induced diaphragmatic dysfunction.
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Indianto, Andi, Aprilia Rossa Ariesta, Erlina Yanuarini, Rikki Sofyan Rizal, and Sukarman Sukarman. "Uniform Deflection in PCI Girder with Diaphragm Installation." IOP Conference Series: Earth and Environmental Science 1117, no. 1 (December 1, 2022): 012035. http://dx.doi.org/10.1088/1755-1315/1117/1/012035.
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Abstract Keramasan Bridge 2 is a bridge with an age of more than 30 years, so it is necessary to review its feasibility and serviceability. Based on visual observations, there are signs of cracks in the transverse and longitudinal directions on the bridge floor. Based on the results of the loading test, it is stated that the deflection on the girder has exceeded the allowable deflection, and the cause of the longitudinal floor crack is caused by the non-uniform vertical movement of the girder. Based on this, it is necessary to strengthen the superstructure first before repairing the bridge floor. The strengthening of the superstructure is carried out by installing a diaphragm between the girders. The diaphragm is an angled steel profile of 100 mm x 100 mm with a thickness of 10 mm. To determine the number and position of diaphragms, two alternatives were analyzed. The first alternative is to add three diaphragms at every 6.275 m distance and the second alternative is the diaphragm at every 3 m distance. The results of the analysis show that the deflection that occurs between the girders after the installation of the diaphragm is uniform. The installation of diaphragms with a distance of 6.275 m and 3 m can increase the uniformity of the girder structure up to 8.12 times and 6.60 times respectively. Whereas the installation of diaphragms with a distance of 6.275 m and 3 m can increase the stiffness of the girder structure up to 10.96 times and 11.26 times, respectively. This shows that adding a diaphragm can provide rigidity and compactness between the girders.
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Werdina, Ghassan M., and Omar Q. Aziz. "Anchorage Zone Stresses Model of Interior Diaphragm for Segmental Box Girder Bridge." Polytechnic Journal 9, no. 2 (December 1, 2019): 171–77. http://dx.doi.org/10.25156/ptj.v9n2y2019.pp171-177.
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Post-tensioning tendons in segmental box girder bridges are usually anchored in very massive diaphragms. This paper presents an analytical investigation of the anchorage zone stresses for an interior pier diaphragm and a rectangular block model (model of diaphragm anchorage zone). The failure load and load-displacement relation for the two cases were compared, a typical diaphragm for a segmental box girder bridge with external prestressing tendons and rectangular block model were analyzed by finite element program (ABAQUS). The anchorage devices were subjected to a prestressing design load which was based on the ultimate strength of the tendons. The magnitude and distribution of stresses were plotted through different paths for both the diaphragm and the block model; also the contours of stress distribution for the diaphragm and block model were compared. The results showed that the stresses and failure load for the diaphragm and rectangular block model were very close.
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Li, Hui, Bo Zhao, and Han Zhu. "Numerical Simulation of Fatigue Performance of Diaphragm of Large-Span Bridge Orthotropic Deck." Complexity 2018 (October 23, 2018): 1–19. http://dx.doi.org/10.1155/2018/3903461.
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Under traffic loads, orthotropic steel bridge slabs suffer from an obvious fatigue problem. In particular, fatigue cracking of diaphragms seriously affects application and development of orthotropic bridge slabs. In the paper, based on cracking status quo of an orthotropic deck diaphragm of a large-span bridge, experimental tests were formulated to test stress distribution states of the diaphragm. The finite element software ABAQUS was used to establish a finite element model of the orthotropic deck diaphragm; numerical simulation was conducted on the basis of the experiments. Simulation results were compared with experimental results, so correctness of the finite element model was verified. Finally, Local Strain Approach (LSA) and Theory of Critical Distance (TCD) were used to conduct life assessment of the orthotropic deck diaphragms, and applicability of two methods was discussed. In this way, a fatigue life assessment method with high accuracy and good operability was provided for fatigue life assessment of orthotropic deck diaphragms.
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Giongo, Ivan, Aaron Wilson, Dmytro Y. Dizhur, Hossein Derakhshan, Roberto Tomasi, Michael C. Griffith, Pierre Quenneville, and Jason M. Ingham. "Detailed seismic assessment and improvement procedure for vintage flexible timber diaphragms." Bulletin of the New Zealand Society for Earthquake Engineering 47, no. 2 (June 30, 2014): 97–118. http://dx.doi.org/10.5459/bnzsee.47.2.97-118.
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Currently there is little guidance available on an experimentally-validated detailed seismic assessment procedure for vintage flexible timber diaphragms such as are routinely encountered in New Zealand unreinforced masonry buildings. The results from recent testing of full-scale diaphragms are presented and interpreted with particular attention given to the definition of shear stiffness and shear strength values, whilst acknowledging that the recommendations derive from a small data set. References are provided to information previously published elsewhere to justify the theoretical framework adopted, and the procedure is linked to ASCE 41-13 for guidance regarding diaphragm scenarios that have not been studied by the authors. A procedure is provided to account for the effects on diaphragm response of supplementary stiffness due to masonry end walls. The performance of several diaphragms that were improved with either overlays or underlays is reported as potential proof-tested standard solutions. The assessment procedure is demonstrated by providing a mock worked example of a detailed diaphragm assessment.
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Wang, Xue Ren, Guang Wang, Wei Zhou, and Jian Li. "Finite Element Analysis of the Overturning Process of Ring-Stiffened Titanium Shperical-Cylindrica Diaphragm for Positive Expulsion Tanks." Applied Mechanics and Materials 526 (February 2014): 217–21. http://dx.doi.org/10.4028/www.scientific.net/amm.526.217.
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The shperical-cylindrica metal diaphragm model is established to simulate with finite element analysis method in the large displacement for the elastic-plastic theory, which is based on the current research on the metal diaphragm for positive expulsion tanks. It shows that the unsteady state on the position of rolling is the main reason for the failure of the diaphragm. Based on the optimization to metal diaphragm's structure, The ring-stiffened metal diaphragm model is established to reduce the unsteady state. The simulation result concludes that the optimization can reduce the unsteady state effectively, which also provides the reference for the improving design of metal diaphragm.
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Mifuji, Shinichiro, Koji Adachi, Tatsunori Tsukioka, and Satomitsu Imai. "Thermal Driving Method and Displacement Properties of a Thin-Film Polyimide Diaphragm for a MEMS Actuator." Key Engineering Materials 523-524 (November 2012): 563–68. http://dx.doi.org/10.4028/www.scientific.net/kem.523-524.563.
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A thin-film polyimide diaphragm for a MEMS actuator was fabricated and its process and mechanical characteristics were investigated. Owing to its low elastic modulus and the thin-film process, a thin-film polyimide diaphragm has a merit in terms of producing a large displacement. Given that merit, spin coating was used for forming a thin film of polyamide, and deep-RIE (Bosch process) was used for fabricating the diaphragm section of the actuator. Thin-film polyimide diaphragms with micrometer-order thickness were fabricated. To drive the diaphragm as an actuator, the following two methods were applied: heat expansion by applying an electric current and volume expansion of a gas-liquid phase-change material confined in a cavity between polyimide diaphragms. As for the former method, an aluminum thin film is deposited on the diaphragm. As for the latter, paraffin (vaporized by heating) is used as the phase-change material. Displacement characteristics for each method were revealed by the experiments. In the case of both methods, displacements of tens of micrometers were outputted. Experiments of driving actuator confirmed that the proposed systems work as actuators. The actuators developed in this research are applicable to micro-pumps for medical and other uses.
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Devi, Rekha, and Sandeep Singh Gill. "Stress and Deformation Analysis of Piezoresistive Square Diaphragm Nano Pressure Sensor." Sensor Letters 17, no. 9 (September 1, 2019): 704–9. http://dx.doi.org/10.1166/sl.2019.4132.
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Pressure sensors are among the most widely used MEMS product as sensors in commercial and industrial applications. The diaphragm structure, thickness, and dimensions along with the placement, size, and shape of the piezo resistors are important in the process of designing a pressure sensor. This paper presents the design and simulation of the square diaphragm to analysis the deformation and stress of various materials as well as for the different thickness of the diaphragms at low pressure in the range of 0.1 to 1.5 bar. The design of diaphragm is as a 10 μm thick square diaphragm with 800 μm edge length are considered, which were analyzed by using ANSYS 17 software. The results show that deformation and stress reduction as in the increase in the thickness, which is directly related to the performance of the diaphragm. CNT based diaphragm also showed the improved performance of the pressure sensor as compared to the silicon and polysilicon material.
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Vasudevan, Rajiv S., Sarathi Kalra, Francesca J. Torriani, and William F. Peacock. "816. Effectiveness of Aseptic Stethoscope Barriers in Allowing Clean Contact for Clostridioides Difficile-Contaminated Stethoscopes." Open Forum Infectious Diseases 7, Supplement_1 (October 1, 2020): S450. http://dx.doi.org/10.1093/ofid/ofaa439.1005.
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Abstract Background Healthcare-associated infections (HAIs), such as C. difficile colitis, pose a significant health risk. C. difficile is a spore-forming gram-positive anaerobic bacillus capable of surviving on various surfaces. While a strong emphasis has been placed on hand-washing and environmental cleaning with bleach products to limit the spread of C. difficile, stethoscope contamination has been poorly addressed. Studies have demonstrated that the stethoscope diaphragm harbors similar levels and type of contamination to one’s hands. While a non-alcohol-based solution is recommended for stethoscope hygiene in settings at risk for C. difficile, the use of an aseptic stethoscope diaphragm barrier has not been evaluated. Our purpose is to evaluate whether C. difficile-contaminated stethoscope diaphragms remain aseptic by the placement of an aseptic diaphragm barrier. Methods Fresh cultures of C. difficile were diluted to 107 CFU/mL. After inoculating 16 stethoscope diaphragms with C. difficile, 8 had an aseptic diaphragm barrier applied, and 8 served as non-barrier controls. Contaminated stethoscopes were placed in an anaerobic incubator, then swabbed at 15 and 30 minutes, 2 and 4 hours, and 1, 2, 3, and 7 days after inoculation, and subsequently plated onto blood, chocolate, and cycloserine-cefoxitin fructose agar. These plates were incubated for 48 hours, and resulting colonies were manually counted. Statistical analysis was performed (RStudio version 1.0.153) by ANOVA (Analysis of Variance) with post-hoc Tukey HSD (Honestly Significant Difference). Results Overall, mean colony count was 33 CFU on the 8 stethoscope diaphragms without barriers, vs zero on those with barriers (p≤ 0.05). Growth rates were greatest at 48 hours, with colony counts as high as 160. While stethoscope diaphragms without barriers had increasing rates of C. difficile culture growth, the presence of the barrier resulted in no growth in 100% of stethoscope diaphragms for up to 1 week after contamination (Figure 1). C. difficile colony counts from stethoscope diaphragms at time-points up to 1 week. Conclusion Aseptic barriers allow C. difficile-contaminated stethoscope diaphragms to remain without bacterial growth for up to a week. Disposable aseptic diaphragm barriers may be effective in preventing the spread of C. difficile. Disclosures William F. Peacock, MD, AseptiScope Inc. (Board Member)
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Matecki, Stefan, Ghiabe H. Guibinga, and Basil J. Petrof. "Regenerative capacity of the dystrophic (mdx) diaphragm after induced injury." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 287, no. 4 (October 2004): R961—R968. http://dx.doi.org/10.1152/ajpregu.00146.2004.
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Duchenne muscular dystrophy is characterized by myofiber necrosis, muscle replacement by connective tissue, and crippling weakness. Although the mdx mouse also lacks dystrophin, most muscles show little myofiber loss or functional impairment. An exception is the mdx diaphragm, which is phenotypically similar to the human disease. Here we tested the hypothesis that the mdx diaphragm has a defective regenerative response to necrotic injury, which could account for its severe phenotype. Massive necrosis was induced in mdx and wild-type (C57BL10) mouse diaphragms in vivo by topical application of notexin, which destroys mature myofibers while leaving myogenic precursor satellite cells intact. At 4 h after acute exposure to notexin, >90% of diaphragm myofibers in both wild-type and mdx mice demonstrated pathological sarcolemmal leakiness, and there was a complete loss of isometric force-generating capacity. Both groups of mice showed strong expression of embryonic myosin within the diaphragm at 5 days, which was largely extinguished by 20 days after injury. At 60 days postinjury, wild-type diaphragms exhibited a persistent loss (∼25%) of isometric force-generating capacity, associated with a trend toward increased connective tissue infiltration. In contrast, mdx diaphragms achieved complete functional recovery of force generation to noninjured values, and there was no increase in muscle connective tissue over baseline. These data argue against any loss of intrinsic regenerative capacity within the mdx diaphragm, despite characteristic features of major dystrophic pathology being present. Our findings support the concept that significant latent regenerative capacity resides within dystrophic muscles, which could potentially be exploited for therapeutic purposes.
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Zaitsev, Borys P., Viktor L. Shvetsov, Oleksandr M. Hubskyi, Serhii A. Palkov, and Tetiana V. Protasova. "Investigation of the Thermal Strength of Steam Turbine Diaphragms with Reduction of Axial Dimensions." Journal of Mechanical Engineering 24, no. 2 (June 30, 2021): 37–49. http://dx.doi.org/10.15407/pmach2021.02.037.
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The problem of reducing the axial dimensions of steam turbine diaphragms is associated with the problem of steam turbine modernization performed by increasing the number of reactive blading stages and using existing foundations. Evaluation of the suitability of diaphragm design versions with established steam flow characteristics was carried out with constraints on short- and long-term strength conditions, as well as the accumulation of axial deflections due to creep. For computational research, there was introduced a methodology using the finite element method and Yu. M. Rabotnov’s theory of strain aging. The calculation of creep was reduced to solving an elastic-plastic problem with a deformation curve, which was represented by an isochronous creep curve for the time chosen. A software was used providing for the automated construction of the original computer diaphragm model with the help of guide-vane profile drawings and axial cross-sections of the diaphragm rim and body, as well as several geometric parameters. The calculated model of a welded diaphragm reproduces the main essential features of the structure, the material properties of its elements, as well as steam load. The exploratory studies of diaphragms with reduced axial dimensions were performed on the example of the second- and third-stage diaphragms of the high-pressure cylinder of the K-325-23.5 steam turbine. The original second- and third-stage diaphragm designs were considered to be basic, in relation to which, according to strength and rigidity parameters, the alternative ones were compared. Calculated data for the basic diaphragm design versions for 100 thousand operating hours were obtained. According to the calculations, maximum deflections are achieved at diaphragm edges, and the stresses, that are maximum at the points where the guide vanes are attached to the diaphragm rim and body, undergo a significant redistribution due to creep. Two approaches to the reduction of the axial dimensions of the second-stage diaphragm design of the steam turbine high pressure cylinder were involved. In the first approach, the reduction of the dimensions was achieved by proportionally reducing the guide-vane profile with a corresponding increase in the number of the guide vanes. In the second approach, the profile remained unchanged, but the axial dimensions of the diaphragm rim and body were reduced. The parameters of strength both in the elastic state at the beginning of operation and in the conditions of creep, as well as the accumulation of axial deflections were investigated. Based on the comparisons with the basic design, it was established that the second approach is more effective. Additional recommendations for the use of more heat-resistant steels for outlet guide vanes and the conditions of diaphragm attachment in the turbine casing are given.
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Schellekens, Willem-Jan M., Hieronymus W. H. van Hees, Michiel Vaneker, Marianne Linkels, P. N. Richard Dekhuijzen, Gert Jan Scheffer, Johannes G. van der Hoeven, and Leo M. A. Heunks. "Toll-like Receptor 4 Signaling in Ventilator-induced Diaphragm Atrophy." Anesthesiology 117, no. 2 (August 1, 2012): 329–38. http://dx.doi.org/10.1097/aln.0b013e3182608cc0.
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Background Mechanical ventilation induces diaphragm muscle atrophy, which plays a key role in difficult weaning from mechanical ventilation. The signaling pathways involved in ventilator-induced diaphragm atrophy are poorly understood. The current study investigated the role of Toll-like receptor 4 signaling in the development of ventilator-induced diaphragm atrophy. Methods Unventilated animals were selected for control: wild-type (n = 6) and Toll-like receptor 4 deficient mice (n = 6). Mechanical ventilation (8 h): wild-type (n = 8) and Toll-like receptor 4 deficient (n = 7) mice.Myosin heavy chain content, proinflammatory cytokines, proteolytic activity of the ubiquitin-proteasome pathway, caspase-3 activity, and autophagy were measured in the diaphragm. Results Mechanical ventilation reduced myosin content by approximately 50% in diaphragms of wild-type mice (P less than 0.05). In contrast, ventilation of Toll-like receptor 4 deficient mice did not significantly affect diaphragm myosin content. Likewise, mechanical ventilation significantly increased interleukin-6 and keratinocyte-derived chemokine in the diaphragm of wild-type mice, but not in ventilated Toll-like receptor 4 deficient mice. Mechanical ventilation increased diaphragmatic muscle atrophy factor box transcription in both wild-type and Toll-like receptor 4 deficient mice. Other components of the ubiquitin-proteasome pathway and caspase-3 activity were not affected by ventilation of either wild-type mice or Toll-like receptor 4 deficient mice. Mechanical ventilation induced autophagy in diaphragms of ventilated wild-type mice, but not Toll-like receptor 4 deficient mice. Conclusion Toll-like receptor 4 signaling plays an important role in the development of ventilator-induced diaphragm atrophy, most likely through increased expression of cytokines and activation of lysosomal autophagy.
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He, Zhubin, Qingsong Zhao, Kun Zhang, Jian Ning, Yi Xu, and Xianggang Ruan. "Study on Stamping–Bulging Process of Thin-Walled Superalloy Diaphragm for S-Shaped Bellows." Materials 17, no. 12 (June 10, 2024): 2829. http://dx.doi.org/10.3390/ma17122829.
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A combined stamping–bulging forming process was proposed to achieve high-precision forming of large-diameter, ultra-thin-walled, superalloy welded S-type corrugated diaphragms. The underlying principle is to enhance the diaphragm’s forming accuracy by increasing the plastic deformation region and reducing springback. Using the ABAQUS version 6.14 finite element analysis software, finite element models were constructed for the stamping, hydraulic bulging, and combined stamping–bulging forming processes of the welded S-type metal corrugated diaphragms. A comparative analysis was conducted on the forming processes of the welded S-type metal corrugated diaphragms under the three forming methods, focusing on equivalent stress, distribution of wall thickness, and forming accuracy. This analysis determined the optimal forming process and the corresponding process parameters for superalloy welded S-type metal corrugated diaphragms. The results show that under a constant drawing force, as the bulging pressure increases, the plastic deformation of the straight sections of the diaphragm becomes more pronounced, resulting in improved shape accuracy. The combined stamping–bulging forming process guarantees the highest degree of shape accuracy for the diaphragm. The optimal process parameters were identified as a 30 t force and a 5 MPa pressure, with a maximum shape error of 0.02 mm. Concerning a plate thickness of 0.3 mm, the maximum deviation rate was found to be 6.7%, which represents a 30% improvement over traditional stamping processes. The maximum wall thinning rate was found to be 3.3%, a 1% reduction compared to traditional stamping processes, confirming the process’s feasibility.
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Sindhanaiselvi, D., R. Ananda Natarajan, and T. Shanmuganantham. "Performance Analysis of Sculptured Diaphragm for Low Pressure MEMS Sensors." Applied Mechanics and Materials 592-594 (July 2014): 2193–98. http://dx.doi.org/10.4028/www.scientific.net/amm.592-594.2193.
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Sculptured or Bossed diaphragm is a specialized geometry with rigid center or boss. This paper presents the outcome of design approaches of sculptured diaphragm structure for low pressure applications. The simulation results are obtained using Intellisuite MEMS CAD design tool. The results indicate that sculptured diaphragm are designed with minimum thickness, compensating the large (a/h) ratio with local stiffening by means of rigid center and better linearity. Further, the maximum stress regions are analyzed for fixing the position of the piezoresistor. Finally, the sensitivity is improved by using the Silicon-On-Insulator (SOI) diaphragms.
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Smuder, Ashley J., Elisa J. Gonzalez-Rothi, Oh Sung Kwon, Aaron B. Morton, Kurt J. Sollanek, Scott K. Powers, and David D. Fuller. "Cervical spinal cord injury exacerbates ventilator-induced diaphragm dysfunction." Journal of Applied Physiology 120, no. 2 (January 15, 2016): 166–77. http://dx.doi.org/10.1152/japplphysiol.00488.2015.
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Cervical spinal cord injury (SCI) can dramatically impair diaphragm muscle function and often necessitates mechanical ventilation (MV) to maintain adequate pulmonary gas exchange. MV is a life-saving intervention. However, prolonged MV results in atrophy and impaired function of the diaphragm. Since cervical SCI can also trigger diaphragm atrophy, it may create preconditions that exacerbate ventilator-induced diaphragm dysfunction (VIDD). Currently, no drug therapy or clinical standard of care exists to prevent or minimize diaphragm dysfunction following SCI. Therefore, we first tested the hypothesis that initiating MV acutely after cervical SCI will exacerbate VIDD and enhance proteolytic activation in the diaphragm to a greater extent than either condition alone. Rats underwent controlled MV for 12 h following acute (∼24 h) cervical spinal hemisection injury at C2 (SCI). Diaphragm tissue was then harvested for comprehensive functional and molecular analyses. Second, we determined if antioxidant therapy could mitigate MV-induced diaphragm dysfunction after cervical SCI. In these experiments, SCI rats received antioxidant (Trolox, a vitamin E analog) or saline treatment prior to initiating MV. Our results demonstrate that compared with either condition alone, the combination of SCI and MV resulted in increased diaphragm atrophy, contractile dysfunction, and expression of atrophy-related genes, including MuRF1. Importantly, administration of the antioxidant Trolox attenuated proteolytic activation, fiber atrophy, and contractile dysfunction in the diaphragms of SCI + MV animals. These findings provide evidence that cervical SCI greatly exacerbates VIDD, but antioxidant therapy with Trolox can preserve diaphragm contractile function following acute SCI.
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Shin, Yun-Ho, and Jeung-Hoon Lee. "Estimation of the Complex Dynamic Stiffness of Inflated Rubber Diaphragms in Pneumatic Springs Using Finite Element Method." Sensors 20, no. 23 (November 25, 2020): 6728. http://dx.doi.org/10.3390/s20236728.
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The accurate modeling of the complex dynamic stiffness of inflated rubber diaphragms in pneumatic springs is necessary for an efficient design of vibration isolation tables for precision instruments, such as optical devices and nano-scale equipment. In addition to pressurized air, rubber diaphragms, essentially employed for the prevention of air leakage, make a significant contribution to the total complex stiffness. To reflect the effect of the dynamic stiffness of the inflated rubber diaphragm on the total complex stiffness during the initial design or design improvement stage, it is desirable to predict the complex stiffness of the inflated rubber diaphragm beforehand. In this paper, an estimation method for the complex stiffness of inflated rubber diaphragms using the commercial finite element method (e.g., ABAQUS) is proposed. The proposed method reflects their dynamic characteristics under the large static deformation by the Mooney–Rivlin and Morman’s constitutive equations. The results of comparison with experimental results indicate that the predictions obtained by the proposed method are congruent with the experimental values of the diaphragm.
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Matsuura, Hiroshi, Hiromitsu Furukawa, Atsushi Kondo, Tamio Tanikawa, and Hideki Hashimoto. "Acoustic analysis of jet atomization for uniform dispersion of nano- and micro-droplets." Journal of Applied Physics 132, no. 22 (December 14, 2022): 224502. http://dx.doi.org/10.1063/5.0125547.
Full textAbstract:
In this study, the mechanisms of jet atomization were analyzed based on a frequency analysis of atomization sounds in the audible range (∼20 kHz). Jet atomization is a two-dimensional, high-speed atomization using a diaphragm, and interesting acoustic signals and atomization phenomena were detected on hydrophobic and hydrophilic diaphragms. The hydrophilic diaphragm strongly interacted and resonated with the surface wave, resulting in symmetrical jet atomization relative to the diaphragm. The resonance between the diaphragm and the surface wave was supported by a calculation of the eigenfrequency of the diaphragm and the coincidence of the droplet diameters as calculated from Lang's equation. Notably, the diaphragm excited by the ultrasonic transducer acted as a new transducer vibrating perpendicular to the transducer. As a result, when the diaphragm and the surface wave were in resonance at 2.4 MHz, a symmetrical two-dimensional high-speed jet atomization was generated in the direction perpendicular to the transducer’s vibration direction. This study also revealed that the atomization state can be determined based on the acoustic analysis. This acoustic analysis of atomization sounds can be applied in more advanced atomization control, such as for providing uniform dispersions of droplets containing DNA, drugs, or microplastics.
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Supinski, Gerald S., and Leigh A. Callahan. "Diaphragmatic free radical generation increases in an animal model of heart failure." Journal of Applied Physiology 99, no. 3 (September 2005): 1078–84. http://dx.doi.org/10.1152/japplphysiol.01145.2004.
Full textAbstract:
Heart failure evokes diaphragm weakness, but the mechanism(s) by which this occurs are not known. We postulated that heart failure increases diaphragm free radical generation and that free radicals trigger diaphragm dysfunction in this condition. The purpose of the present study was to test this hypothesis. Experiments were performed using halothane-anesthetized sham-operated control rats and rats in which myocardial infarction was induced by ligation of the left anterior descending coronary artery. Animals were killed 6 wk after surgery, the diaphragms were removed, and the following were assessed: 1) mitochondrial hydrogen peroxide (H2O2) generation, 2) free radical generation in resting and contracting intact diaphragm using a fluorescent-indicator technique, 3) 8-isoprostane and protein carbonyls (indexes of free radical-induced lipid and protein oxidation), and 4) the diaphragm force-frequency relationship. In additional experiments, a group of coronary ligation animals were treated with polyethylene glycol-superoxide dismutase (PEG-SOD, 2,000 units·kg−1·day−1) for 4 wk. We found that coronary ligation evoked an increase in free radical formation by the intact diaphragm, increased diaphragm mitochondrial H2O2 generation, increased diaphragm protein carbonyl levels, and increased diaphragm 8-isoprostane levels compared with controls ( P < 0.001 for the first 3 comparisons, P < 0.05 for 8-isoprostane levels). Force generated in response to 20-Hz stimulation was reduced by coronary ligation ( P < 0.05); PEG-SOD administration restored force to control levels ( P < 0.03). These findings indicate that cardiac dysfunction due to coronary ligation increases diaphragm free radical generation and that free radicals evoke reductions in diaphragm force generation.
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Belyaev, Leonid, Aleksey V. Zhdanov, and Aleksandr Ivanchenko. "Computational and Experimental Methods of Strength Analysis of Polyurethane Diaphragms Operating under Cyclic Loadings." Key Engineering Materials 910 (February 15, 2022): 779–86. http://dx.doi.org/10.4028/p-azoxb8.
Full textAbstract:
In this paper, the algorithm for strength analysis of diaphragms made of elastomers is described, and the strength analysis of the diaphragm made of polyurethane "Vitur" T-1413-85 is carried out. The results obtained showed that the description of the material behavior using the Moony-Rivlin model (5 parameters) gives the greatest accuracy. A comparison of the results of modeling the stress-strain state of the diaphragm and the experimental studies carried out to determine the displacements confirmed the adequacy of the chosen model (average correlation coefficient between numerical simulation and experiment R2 = 0.98) for both studied diaphragm thicknesses. The conducted evaluation of the diaphragm resource according to the criteria of fatigue failure showed the correctness of the selected models of durability.
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Lewis, M. I., W. Z. Zhan, and G. C. Sieck. "Adaptations of the diaphragm in emphysema." Journal of Applied Physiology 72, no. 3 (March 1, 1992): 934–43. http://dx.doi.org/10.1152/jappl.1992.72.3.934.
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In adult male hamsters the influence of emphysema (EMP) on the in vitro contractile and fatigue properties and the histochemical, morphometric, and metabolic properties of muscle fibers in the costal diaphragm was determined 6 mo after the administration of either elastase or saline (controls, CTL). Isometric contractile properties were determined in vitro using supramaximal direct muscle stimulation. Optimal fiber length for force generation was significantly shorter in the EMP than in the CTL diaphragm. Maximum specific force (i.e., force per unit area) was 25% lower than CTL. Fatigue resistance was significantly improved in the EMP diaphragm compared with CTL. Diaphragm muscle fibers were classified as type I or II on the basis of histochemical staining for myofibrillar adenosinetriphosphatase after alkaline preincubation. The proportions of type I and II fibers were similar between the two groups. Cross-sectional areas of type II fibers were 30% larger in EMP than in CTL diaphragms. Succinate dehydrogenase activities of both type I and II fibers were higher in EMP than in CTL diaphragms. The number of capillaries surrounding both type I and II fibers increased with EMP, but in proportion to the hypertrophy of these fibers. Thus, capillary density (number of capillaries per fiber cross-sectional area) remained unchanged. We postulate that these contractile, morphometric, and metabolic adaptations reflect an increased activation of the diaphragm in response to the loads imposed by EMP.
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Trotsenko, Yaroslav. "NUMERICAL SIMULATION OF A FLUID FLOW IN THE CYLINDRICAL DUCT CONTAINING TWO DIAPHRAGMS WITH ORIFICES OF DIFFERENT DIAMETERS." Bulletin of the National Technical University "KhPI". Series: Mathematical modeling in engineering and technologies, no. 1 (August 1, 2023): 198–204. http://dx.doi.org/10.20998/2222-0631.2023.01.29.
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The flow of a viscous incompressible fluid in a cylindrical duct with two serial diaphragms with orifices of different diameters was studied based on the numerical solution of the unsteady Navier-Stokes equations. The solution algorithm was based on the finite volume method using second-order accurate difference schemes in both space and time. The TVD (Total-Variation Diminishing) form of a central-difference scheme with a flux limiter was used for the interpolation of the convective terms. The combined evaluation of the velocity and pressure fields was carried out using the PISO (Pressure Implicit Split Operator) procedure. The problem was solved using OpenFOAM (Open-source Field Operation And Manipulation) open-source toolkit libraries using the computing power of the cluster supercomputer of the V.M. Glushkov Institute of Cybernetics of the National Academy of Sciences of Ukraine. It was shown that within a certain range of the diameter ratio of the orifices of the diaphragms, a circulation movement is established in the cavity between the diaphragms. The boundary layer breaks off from the surface of the first diaphragm and forms an annular shear layer. When approaching the second diaphragm, a sequence of ring vortices is formed in it, which interact with the surface of the diaphragm and lead to the emergence of tonal sound. When the ratio of the orifice diameter of the second diaphragm to the first decreases, the share of the jet’s kinetic energy, which participates in the circulation in the middle of the cavity between the diaphragms, increases. As a result, the amplitude of velocity fluctuations in the orifice of the second diaphragm decreases. When the ratio of the diameters of the orifices increases, the share of energy involved in the circulation decreases, and when a certain value of the ratio is reached, the interaction between the vortices in the shear layer and the surface of the diaphragm does not occur. As a result, the excitation of the tonal sound stops. The Strouhal number of self-oscillations practically does not change when the diameter ratio of the orifices changes. During the calculations, two different modes of self-oscillation were obtained, which is consistent with previous works.
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Vershkov, V. A., D. V. Sarychev, D. A. Shelukhin, A. R. Nemets, S. V. Mirnov, I. E. Lyublinski, A. V. Vertkov, and M. Yu Zharkov. "Use of Lithium Capillary Structures in Ohmic Discharges of T-10 Tokamak." Plasma Physics Reports 50, no. 3 (March 2024): 283–309. http://dx.doi.org/10.1134/s1063780x2460021x.
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Abstract The results of experiments at the T-10 tokamak using lithium capillary-porous structures are presented. It is shown that lithium sputtering under conditions of graphite diaphragms can significantly reduce deuterium recycling and the level of impurities in the plasma. At the same time, recycling increases significantly five discharges after the start of the day of the experiment, and the effect of reducing the level of impurities persists for 150–300 discharges. The results of using a capillary-porous structure with lithium filling as a movable rail diaphragm in the T-10 configuration with tungsten main diaphragms are presented. The introduction of a lithium diaphragm into the SOL region makes it possible to reduce recycling and obtain discharges with an effective plasma charge approaching unity. In this case, the effect increases as the lithium sputtered in the chamber is accumulated. It is shown experimentally that a capillary-porous structure with lithium filling can be used as a main diaphragm with longitudinal plasma heat fluxes up to 3.6 MW/m2. However, a necessary condition is the complete impregnation of the porous structure with lithium and the prevention of extrusion of lithium into the discharge as a result of the interaction of the current flowing to the diaphragm with the toroidal magnetic field. Experiments have shown that to obtain discharges with a small lithium admixture, a strong gas injection of deuterium or impurity is required to reduce the temperature of the plasma periphery and effective cooling of the diaphragm below 450°C. Otherwise, the diaphragm transfers into a strong evaporation mode with high lithium flows, which lead to a significant increase in the lithium concentration in the plasma. Strong evaporation reduces the heat inflow and stabilizes the diaphragm temperature.