Academic literature on the topic 'Determination of equivalent pressure of mudflow'
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Journal articles on the topic "Determination of equivalent pressure of mudflow"
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Shaazizov, farrukh shoakbarovich, and oybek farhodjon ugli Vokhidov. "ASSESSMENT OF DAMAGE DURING THE FORMATION AND PASSAGE OF MUDFLOWS IN THE TASHKENT REGION." Journal of agro processing 4, no. 5 (2022): 4. https://doi.org/10.5281/zenodo.7340588.
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Mountainous and largely foothill areas of the Republic of Uzbekistan are mudflow hazardous. In Tashkent region, there are two mudflow river basins (dangerous in relation to the manifestation of mudflows): the Chirchik river basin and the Akhangaran river basin. Based on the results of long-term observations of the Uzhydromet service, a digital map of the mudflow hazard in the Tashkent region for a century was compiled. The method for determining the damage from the action of mudflows on a specific object consists in determining the equivalent mudflow pressure according to its initial parameters. According to the methodology for assessing damage in the event of a natural emergency, the main parameters of the damaging factors were determined during the passage of a mudflow in the event of intense rainfall. The calculations were performed for two scenarios: 1) with dangerous rainfall with an intensity of 30 mm per day; 2) in case of especially dangerous rainfall with an intensity of 60 mm per day. Based on the calculations performed, the amount of damage to the national economy of the Tashkent region was determined during the passage of a mudflow caused by intense rainfall.
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Shaazizov, Farrukh. "Assessment of damage during the formation and passage of mudflows in the Tashkent region." E3S Web of Conferences 264 (2021): 03042. http://dx.doi.org/10.1051/e3sconf/202126403042.
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Mountainous and largely foothill areas of the Republic of Uzbekistan are mudflow hazardous. In the Tashkent region, there are two mudflow river basins (dangerous concerning the manifestation of mudflows): the Chirchik river basin and the Akhangaran river basin. Based on the results of long-term observations of the Uzhydromet service, a digital map of the mudflow hazard in the Tashkent region for a century was compiled. The method for determining the damage from the action of mudflows on a specific object consists of determining the equivalent mudflow pressure according to its initial parameters. According to the methodology for assessing damage in the event of a natural emergency, the main parameters of the damaging factors were determined during the passage of a mudflow in the event of intense rainfall. The calculations were performed for two scenarios: 1) with dangerous rainfall with an intensity of 30 mm per day; 2) in case of especially dangerous rainfall with an intensity of 60 mm per day. Based on the calculations performed, the amount of damage to the national economy of the Tashkent region was determined during the passage of a mudflow caused by intense rainfall.
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Markarian, A. A., E. Yu Kudelya, I. D. Makitruk, N. Yu Pilyavskaya, D. A. Virki, and A. V. Bulatov. "Assessment of the Equivalence of Methods for the Determination of the Vapor Pressure of Oil and Oil Products." Measurement Standards. Reference Materials 19, no. 5 (2024): 143–53. http://dx.doi.org/10.20915/2077-1177-2023-19-5-143-153.
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Current regulatory documents in Russia establish the need for testing laboratories to determine such parameters as saturated vapor pressure using the Reid method, air saturated vapor pressure, total vapor pressure of crude oil. In analytical practice, appropriate reference materials are used for measurement quality control, method validation, metrological traceability establishment, and other purposes. In addition, the calculation of various vapor pressure equivalents using correlation equations (DVPE – dry vapor pressure equivalent, RVPE – Reid vapor pressure equivalent, etc.) is regulated by appropriate methods for determining vapor pressure. Vapor pressure is a method-dependent parameter; so many producers of reference materials use interlaboratory experiment as a way to establish a certified value. Thus, when conducting an interlaboratory experiment in the process of certification of reference materials, it was revealed that laboratories can incorrectly interpret the obtained experimental data – consider values of the air saturated vapor pressure, total vapor pressure and even calculated vapor pressure equivalents as the Reid vapor pressure. To solve this problem, the authors of this work set the goal of assessing the equivalence of methods for determining the vapor pressure of oil and oil products used in testing laboratories in order to identify the key characteristics of the stated methods and assess their equivalence. The article discusses methods the vapor pressure determination using an automatic vacuum chamber and a Reid bomb. Various matrices of reference materials (hydrocarbons, gasoline, commercial oil, gas condensate) were investigated, and the calculated vapor pressure equivalents were obtained and compared. It was shown that the air saturated vapor pressure, dry vapor pressure equivalent, Reid vapor pressure equivalent, and total vapor pressure cannot be equated to the saturated vapor pressure values determined by the Reid method. A comparative assessment of methods for determining the vapor pressure of oil and oil products used in testing laboratories can be of assistance to developers of regulatory documents for oil, gas condensate, and motor gasoline, revealing the need to separate the requirements for vapor pressure parameters of the considered objects of analysis and providing empirical material.
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Hagen, Anette B., Bård Nyhus, Michael R. Gerhardt, et al. "Experimental determination of equivalent hydrogen gas pressure from electrochemical hydrogen charging." International Journal of Hydrogen Energy 82 (September 2024): 1146–56. http://dx.doi.org/10.1016/j.ijhydene.2024.02.117.
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Jung, Dong Soo, Hyoung Eui Kim, Sung Hun Kim, and E. Sok Kang. "Development of Accelerated Life Test Method of Hydraulic Pump." Key Engineering Materials 326-328 (December 2006): 1861–64. http://dx.doi.org/10.4028/www.scientific.net/kem.326-328.1861.
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This paper proposes a new accelerated life test method of hydraulic pump used in vehicles, which have multiple alternating loads. For determination of life time of hydraulic pump for given field conditions with respect to duty cycle, the equivalent load and speed of this unit has to be determined. Equivalent load and speed can be calculated from the given duty cycle using the predominant theory for cumulative fatigue damage. Finally, we can perform accelerated life test on hydraulic pump by determination of test pressure and speed from calculated equivalent cumulative damage per working cycle and weighted average speed.
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Wang, Jian, Tao Wei, Zhuoyang Song, Rui Chen, and Qiu He. "Determination of the Equivalent Length for Evaluating Local Head Losses in Drip Irrigation Laterals." Applied Engineering in Agriculture 38, no. 1 (2022): 49–59. http://dx.doi.org/10.13031/aea.14735.
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HighlightsA hydraulic model was used to determine the value of the equivalent length for evaluating local emitter head losses in drip laterals.Dimensional analysis was used to develop an equation for predicting the equivalent length.The effects of the design variables on the equivalent length were investigated.The accuracy of the equation was validated by a previous experiment and an alternative hydraulic model.Abstract. The equivalent length is widely used in current hydraulic models to estimate local emitter head losses for the analysis and design of drip irrigation laterals. The accurate evaluation of the equivalent length is therefore required in the lateral design procedure. In this study, a finite element model was used to develop an equation to predict the equivalent length. Eight design variables were selected, and 32 lateral cases were generated using the orthogonal design. The total local head loss in the 32 laterals were firstly calculated using the local head loss coefficient multiplied by the kinetic head. The solutions were considered as exact values and being equivalent to friction head losses, and the equivalent length was computed using the Darcy-Weisbach equation. Dimensional analysis and regression procedures were then used to obtain the prediction equation related to the selected variables. The results show that the converted equivalent lengths accurately estimated the local head losses in the 32 laterals. The local head loss coefficient was the most important factor for the equivalent length, followed by the lateral diameter. The effects of the lateral inlet pressure head, flow exponent, nominal flow rate of emitter, number of emitter, emitter spacing and lateral slope were not significant. Two models were developed to predict the equivalent length, and to calculated the total local head losses. The results demonstrated satisfactory agreement with the measured value available in a previous experimental study, with RMSE = 0.202 and 0.162 m for the full and simplified model, respectively. The percent error between the measured and calculated total head losses using simplified model was from -16.5% to 14.8%, and the Camargo and Sentelhas coefficient c was higher than 0.98. The equations were therefore capable for evaluating the local head loss in the hydraulic design of drip irrigation laterals. Keywords: Dimensional analysis, Finite element method, Hydraulic design, Pressure head, Uniformity.
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Lazarescu, Lucian, Ioan Pavel Nicodim, Dan Sorin Comsa, and Dorel Banabic. "A Procedure for the Evaluation of Flow Stress of Sheet Metal by Hydraulic Bulge Test Using Elliptical Dies." Key Engineering Materials 504-506 (February 2012): 107–12. http://dx.doi.org/10.4028/www.scientific.net/kem.504-506.107.
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The paper describes a new experimental procedure for the determination of the curves relating the equivalent stress and equivalent strain of sheet metals by means of the hydraulic bulge tests through elliptical dies. The procedure is based on an analytical model of the bulging process and involves the measurement of only two parameters (pressure acting on the surface of the specimen and polar deflection).
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Zhao, Jie, Zhan Qi Guo, and Gai Fei Peng. "Vapor Pressure Modeling for Fire Damage Assessment of HPC." Key Engineering Materials 417-418 (October 2009): 509–12. http://dx.doi.org/10.4028/www.scientific.net/kem.417-418.509.
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High-performance concrete will undergo severe damage under fire conditions. It is well known that vapor pressure induced by high temperatures plays an important role in the damaging process. This paper presents a method of vapor pressure modeling, called equivalent expansion method, which can be implemented in FEM analysis. The modeling procedure consists of two parts, i.e. vapor pressure determination and vapor pressure modeling incorporated in FEM analysis. In order to make analysis more accurate, steam table is employed instead of ideal gas equation.
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Lazarević, Miloš, Bogdan Nedić, Jovica Bogdanov, and Stefan Đurić. "Determination of the critical distance in the procedure of explosive welding." Vojnotehnicki glasnik 68, no. 4 (2020): 823–44. http://dx.doi.org/10.5937/vojtehg68-26683.
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Introduction/purpose: When performing the explosive welding procedure, for the safety of workers, it is necessary to take into account the minimum distance between the workers and the place of explosion at the time of explosion. Negligence can cause temporary hearing loss, rupture of the eardrum and in some cases even the death of workers. The aim of this paper is to determine the critical distance based on the mass of explosive charge required for explosive welding, provided that the limit pressure is 6.9 kPa in the case of temporary hearing loss and 35 kPa in the case of eardrum rupture. This paper does not take into account other effects of the explosion than those caused by the shock wave. Methods: Depending on the type of explosion, the equivalent explosive mass was calculated. Based on the equivalent explosive mass and the limit pressure, the minimum distances were calculated using the Sadovsky and Kingery-Bulmash equations. Results: The corresponding tables show the results of the calculation of the critical distance of workers from the place of the explosion when there may be temporary hearing loss or rupture of the eardrum. The calculated value of the critical explosion distance by the Kingery-Bulmash method, under the condition of the maximum pressure for temporary hearing loss, is 5.62% lower than the distance value obtained by the Sadovsky method while the value of the critical explosion distance calculated by the Kingery-Bulmash method, under the condition of the maximum pressure for eardrum rupture, is 7.83% lower than the value obtained by the Sadovsky method. Conclusion: The results of the calculation showed that the critical distance from the explosion can be successfully calculated and that the obtained values have small differences depending on the applied calculation method.
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Seshadri, R., та H. Indermohan. "Lower Bound Limit Load Determination: The mβ-Multiplier Method". Journal of Pressure Vessel Technology 126, № 2 (2004): 237–40. http://dx.doi.org/10.1115/1.1688780.
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The existing lower bound limit load determination methods, that are based on linear elastic analysis such as the classical and mα-multiplier methods, have a dependence on the maximum equivalent stress. These methods are therefore sensitive to localized plastic action, which occurs in components with thin or slender construction, or those containing notches and cracks. Sensitivity manifests itself as relatively poor lower bounds during the initial elastic iterations of the elastic modulus adjustment procedures, or oscillatory behavior of the multiplier during successive elastic iterations leading to limited accuracy. The mβ-multiplier method proposed in this paper starts out with Mura’s inequality that relates the upper bound to the exact multiplier by making use of the “integral mean of yield.” The formulation relies on a “reference parameter” that is obtained from considering a distribution of stress rather than a single maximum equivalent stress. As a result, good limit load estimates have been obtained for several pressure component configurations.
Dissertations / Theses on the topic "Determination of equivalent pressure of mudflow"
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Kok, Chuen Wah. "Determination of the pressure equivalent noise signal of vector sensors in a hybrid array." Thesis, Monterey, California. Naval Postgraduate School, 2012. http://hdl.handle.net/10945/27855.
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The advent of particle velocity sensors as a viable addition to traditional pressure-based sensors in acoustics has fueled considerable research into the additional capabilities they might bring. Previous thesis work performed at NPS successfully demonstrated a working acoustic beamformer using a hybrid array comprised of a single conventional omnidirectional microphone and two 3D Microflown Ultimate Sound Probes in an anechoic chamber. These Microflown sensors are vector sensors. They have integrated directionality through the inclusion of three orthogonal particle velocity sensors with a microphone. Unfortunately, the signals of the particle velocity sensors obtained outside in a light, gusting wind were unusable due to broadband noise. Since the fundamental limit to detecting quiet targets depends on the noise floor, the aim of this thesis was to perform an in situ measurement of the pressure equivalent noise floor of all sensors in the array and to minimize the wind noise. Noise levels measured in an anechoic chamber were 915 dB higher than the levels expected from the sensors alone. The additional noise is attributed to the data acquisition equipment. The use of an ACO WS7 windscreen was shown to be extremely effective in mitigating broadband wind noise.
Book chapters on the topic "Determination of equivalent pressure of mudflow"
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Sharma, Binu, and Animesh Deka. "Static Compaction Test and Determination of Equivalent Static Pressure." In Lecture Notes in Civil Engineering. Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-13-0899-4_1.
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Guetif Fessi Zahra and Bouassida Mounir. "Settlement estimation of soils reinforced by columns using a poroelastic model." In Proceedings of the 16th International Conference on Soil Mechanics and Geotechnical Engineering. IOS Press, 2005. https://doi.org/10.3233/978-1-61499-656-9-1355.
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A significant part of the consolidation of soft clay fitted with vertical drains (or stone columns) occurs during a step by step embankment loading. In order to schedule the loading program, it is necessary to predict the settlement evolution during the construction process. A unit cell model, made up with one column surrounded by saturated soft clay overlaid by drained layer, is considered with oedometric conditions. An analytical poroelastic solution is derived that provides, in addition to the degree of radial consolidation and excess pore water pressure dissipation, the evolution with time of the reinforced soil settlement. The latter is predicted by introducing the concept of “equivalent membrane” assuming a uniform excess pore water pressure in the soft clay. The Barron's factor time of radial consolidation is also adopted that provides the determination of the permeability of this “equivalent membrane”. The results of the proposed method are illustrated as a function of the substitution factor.
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GHISTA, DHANJOO N., LI LIU, LIANG ZHONG, et al. "LEFT VENTRICULAR (LV) PRESSURE INCREASE MECHANISM DURING ISOVOLUMIC CONTRACTION, AND DETERMINATION OF THE EQUIVALENT LV MYOCARDIAL FIBERS ORIENTATION." In Clinically-Oriented Biomedical Engineering. WORLD SCIENTIFIC, 2007. http://dx.doi.org/10.1142/9789812775597_0006.
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Martinho Simões, José A., and Manuel Minas da Piedade. "Isoperibol Reaction-Solution Calorimetry." In Molecular Energetics. Oxford University Press, 2008. http://dx.doi.org/10.1093/oso/9780195133196.003.0012.
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The determination of enthalpies of reaction in solution, using isoperibol reaction-solution calorimetry, is often the easiest and most accurate method of determining enthalpies of formation of compounds that cannot be studied by combustion calorimetry. The technique was pioneered by Thomsen who, between 1882 and 1886, performed thermochemical measurements involving the solution of various substances in liquids (e.g., diluted acids). Many types of isoperibol reaction-solution calorimeters have been developed since then. The designs vary according to the nature of the reactions of interest. One of the most widely used consists of a vessel, such as the one shown in figure 8.1, immersed in a thermostatic water bath. The sample is sealed inside a thin-walled glass ampule A, fixed to an ampule breaking system B in the calorimeter head C. The calorimeter head also supports the temperature sensor D, the stirrer E, and an electrical resistance F, used for calibration of the apparatus. The Dewar vessel G, containing the solution to be reacted with the sample, is adjusted to C. The assembled calorimetric vessel is transferred to the thermostatic bath, and from then on, the experimental procedure closely follows that already described in section 7.1 for isoperibol static-bomb combustion calorimetry. The reaction is initiated at the end of the fore period by pushing down the plunger H and breaking the ampule against a pin situated at the bottom of the ampule breaking system B. As a result of the calorimetric experiment, a temperature-time curve such as the one in figure 7.2 is obtained. Note that figure 7.2 is typical of an exothermic process. In the case of an endothermic process, a decrease of the temperature of the calorimetric system is observed during the reaction period. The experiments are usually carried out at atmospheric pressure and the initial goal is the determination of the enthalpy change associated with the calorimetric process under isothermal conditions, ΔHICP, usually at the reference temperature of 298.15 K. This involves the determination of the corresponding adiabatic temperature change, ΔTad, from the temperature-time curve just mentioned, by using one of the methods discussed in section 7.1; the determination of the energy equivalent of the calorimeter in a separate experiment.
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Major, Zoltán, Edina Koch, and Éva Lublóy. "Change in Stiffness of Reinforced Concrete Tunnel Walls and Its Effect Under Fire Load." In Advances in Transdisciplinary Engineering. IOS Press, 2024. http://dx.doi.org/10.3233/atde240565.
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This article uses the knowledge gained from tunnel fires to address the structural analysis of tunnel walls during fire exposure. The designing at normal temperature and its theoretical background are discussed in the literature. As these books did not yet deal with the issue of fire protection designing, we tried to supplement the existing theoretical knowledge with the knowledge provided by the relevant standards for reinforced concrete tunnel walls. In addition, we have tried to add our own individual ideas to the theory where we felt that there were gaps. The theoretical summary has been compiled in such a way that it can be easily transferred and applied to everyday practice. In this article, we discuss in detail the calculation of the internal forces in tunnel walls during fire exposure. Due to space constraints, the issue of designing at normal temperatures is only touched upon in this article, limiting it to the knowledge available in the literature. Since finite element modelling has become a commonly used technique in tunnel design since the 1970s, we use its potential to investigate the effects of earth pressure and surface loads on the tunnel walls during fire and their changes, using specific software for geotechnical design. In accordance with the limitations of the scope, the determination of the equivalent thickness and the modulus of elasticity of the tunnel wall is also presented in order to determine the internal forces during the fire action.
Conference papers on the topic "Determination of equivalent pressure of mudflow"
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Kotulski, J. D., M. U. Anderson, B. C. Brock, J. Gomez, R. A. Graham, and C. N. Vittitoe. "Determination of equivalent circuit for PVDF shock-pressure gauges." In High-pressure science and technology—1993. AIP, 1994. http://dx.doi.org/10.1063/1.46164.
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Seshadri, R., та H. Indermohan. "Lower Bound Limit Load Determination: The mβ-Multiplier Method". У ASME 2003 Pressure Vessels and Piping Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/pvp2003-1887.
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The existing lower bound limit load determination methods that are based on linear elastic analysis such as the classical and mα-multiplier methods have a dependence on the maximum equivalent stress. These methods are therefore sensitive to localized plastic action, which occurs in components with thin or slender construction, or those containing notches and cracks. Sensitivity manifests itself as relatively poor lower bounds during the initial elastic iterations of the elastic modulus adjustment procedures, or oscillatory behavior of the multiplier during successive elastic iterations leading to limited accuracy. The mβ-multiplier method proposed in this paper starts out with Mura’s inequality that relates the upper bound to the exact multiplier by making use of the “integral mean of yield.” The formulation relies on a “reference parameter” that is obtained by considering a distribution of stress rather than a single maximum equivalent stress. As a result, good limit load estimates have been obtained for several pressure component configurations.
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Schildberg, Hans-Peter, Jan P. M. Smeulers, and Gersom Pape. "Experimental Determination of the Static Equivalent Pressures of Gas Phase Detonations in Pipes and Comparison With Numerical Models." In ASME 2013 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/pvp2013-97677.
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In order to determine the effective load of gas phase detonations on pipe walls (“static equivalent pressure”), comprehensive experiments have been conducted in 48.3×2.6 and 114.3×3.6 pipes (outer diameter [mm] × wall thickness [mm]), in which deflagrative explosions of stoichiometric C2H4/O2/N2-mixtures at 20 °C underwent the transition to detonation. Initial pressures were chosen high enough to produce detonation pressures that caused significant bulging of the pipe walls. All 8 different pressure scenarios that can be distinguished for gas phase detonations in pipes were addressed by the experiments, even the extremely rare case of having the deflagration to detonation transition occurring within about 1 pipe diameter a head of blind flange which yields the largest static equivalent pressure of all scenarios. By these tests it was possible to (1) validate the predictions of recently developed numerical models for predicting the structural response of the pipe wall and to (2) determine the static equivalent pressure of gas phase detonations in pipes even for those detonative pressure scenarios for which a reliable pressure/space/time profile required as input for the numerical models is at present not yet available. Once the static equivalent pressure is known, the well-established pressure vessel design guidelines, which can only cope with static loads, can be applied for detonation pressure proof pipe design in all those cases where the detonation speed is not close to the propagation speed of the flexural waves in the pipe. Furthermore, preliminary information was obtained about which of the 8 detonative pressure scenarios only depends on the Chapman-Jouguet pressure ratio of the involved mixture and which scenarios will also depend on other characteristic parameters of the involved mixture (difference between initial temperature and auto ignition temperature, ignition delay time).
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Schildberg, Hans-Peter. "Experimental Determination of the Static Equivalent Pressures of Detonative Decompositions of Acetylene in Long Pipes and Chapman-Jouguet Pressure Ratio." In ASME 2014 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/pvp2014-28197.
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Gaseous acetylene (C2H2), which is used in industry in large quantities, is well known for being prone to detonative decomposition. Existing guidelines provide advice for a safe handling but are still deficient with regard to quantifying the static equivalent pressures experienced by the wall of a pipe when exposed to an internal detonative decomposition reaction. By applying the pipe wall deformation method we determined the static equivalent pressures occurring in long pipes. Once the static equivalent pressure is known, the well-established pressure vessel design guidelines, which can cope with static loads, can be applied for detonation pressure proof pipe design in all cases where the detonation speed is not close to the propagation speed of the flexural waves in the pipe. The tests revealed further important new details characterizing the detonative decomposition of C2H2: 1) The static equivalent pressure at the location of the occurrence of the deflagration to detonation transition (DDT) turned out to decrease relatively with increasing initial pressure. 2) When exceeding an initial pressure of approximately 12 bar abs there was no longer a stage of instable detonation after the occurrence of the deflagration to detonation transition, but the reaction front immediately propagated as a stable detonation. 3) It was found that the Chapman-Jouguet theory, which provides reasonably precise predictions for the propagation speed of the stable detonation and the Chapman-Jouguet pressure ratio in the case of common stoichiometric combustible/oxidant mixtures, seems to fail in the case of the decomposition of C2H2. A possible reason for this could be the fact that the decomposition reaction, in contrast to all other combustion reactions, generates both gaseous and solid reaction products. 4) By combining the results of recent work on detonations in ethylene/O2/N2-mixtures published in PVP2013-97677 and the present tests, a good estimate for the Chapman-Jouguet pressure ratio of the detonative decomposition reaction of C2H2 could be derived.
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Schildberg, Hans-Peter. "Experimental Determination of the Static Equivalent Pressures of Detonative Explosions of Stoichiometric H2/O2/N2-Mixtures in Long and Short Pipes." In ASME 2015 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/pvp2015-45286.
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As continuation of recently published experimental work [1,2], the static equivalent pressures (“pstat“) of the different detonative pressure scenarios occurring in stoichiometric H2/O2/N2 mixtures were determined in long and short pipes at ambient initial temperatures (20 °C) and initial pressures ranging from 4 bar abs to 35 bar abs. The pipes used for the tests were about 10 m long and had radial dimensions of 48.3×2.6 and 114.3×3.6 (outer diameter [mm] × wall thickness [mm]). The O2 content was varied from about 10 vol.-% to the highest value possible in stoichiometric mixtures (33.3 vol.-%). For the tests in the long pipes the focus was on the variation of the ratio between the static equivalent pressure at the point where transition from deflagration to detonation occurred and the static equivalent pressure in the region of the stable detonation (pstat_DDT_long / pstat_stable). The ratio attained a maximum of about 5 at 14.78 vol.-% O2 (stoichiometric H2/air) and decays to 1 when increasing the O2 content to 24 vol.-%. This drop indicates that with increasing O2 content ever less precompression is required to cause auto ignition in the precompressed gas directly ahead of the deflagrative flame front. For mixtures of H2 with N2-diluted air the ratio exhibits a slight decrease which is in contrast to what would be expected and is not yet understood. The results obtained for the ratio between pstat of scenarios 3 and 4 (stable detonation and reflected stable detonation) and the Chapman-Jouguet pressure of the investigated gas mixtures confirmed the findings presented in PVP2013-97677 for ethylene/air-mixtures. For mixtures of H2 and slightly diluted air the load for the reflected instable detonation was found to be about 7 · pstat_stable, the load at the DDT in the short pipe is 6.6 · pstat_stable and the load for coalescence of DDT and reflection is about 14 · pstat_stable.
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van Zyl, Gys. "Determination of Target Bolt Tension for Flanges With Lens Gaskets." In ASME 2017 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/pvp2017-65439.
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A lens gasket is a specific type of metallic ring gasket that is usually only deployed in high pressure gas applications where a high integrity bolted flange joint is required. Lens gaskets are not common in ASME design and there are no ASME rules that guide the design of flanges with lens gaskets, nor are there ASME standards to control lens gasket specifications. Lens gaskets present a special challenge when determining target bolt tension values for flange assembly. For calculating target bolt tension, the gasket seating width is an important parameter. With lens gaskets, the gasket seating width depends on the applied bolt tension, therefore calculation of bolt tension is by nature an iterative process. In these flange joints, the lens gasket has spherical machined surfaces that are in contact with conical gasket seats in the flanges. At low bolt tensions, gasket contact is nearly equivalent to line contact. At high bolt tensions, finite contact widths are developed, sometimes involving plastic deformation of the gasket. This paper will present a method that was developed to determine target bolt tension for a lens gasket bolted flange. Reference will be made to European standards that address lens gaskets, and the results of finite element analysis studies that were used to validate the calculation method will be presented. The successful deployment of the outcome of this work for all the lens gasket flange joints on a plant will be discussed.
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Zhu, Xian-Kui, Sebastian Cravero, and Claudio Ruggieri. "Determination of J-R Curve for X60 Pipeline Steel Using SENT Specimens and Normalization Method." In ASME 2009 Pressure Vessels and Piping Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/pvp2009-78089.
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The normalization method is adopted in this paper to determine J-R curves for X60 pipeline steel using single-edge notched tension (SENT) specimens. A resistance curve procedure associated with the normalization method is developed to estimate crack extension, calculate crack growth corrected J-integral and generate a J-R curve directly using load-displacement data from a single test on SENT specimens. Based on experimental data for a typical pin-loaded SENT specimen, J-R curve for X60 pipeline steel is obtained by the normalization method and the conventional elastic unloading compliance method. The results show that the normalization method is simple and cost-effective, and can obtain J-R curves equivalent to the unloading compliance method in use of SENT specimens.
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Schildberg, Hans-Peter. "Experimental Determination of the Static Equivalent Pressures of Detonative Explosions of Stoichiometric CH4/O2/N2-Mixtures and CH4/O2-Mixtures in Long Pipes." In ASME 2016 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/pvp2016-63223.
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In the recent past (PVP2013-97677, PVP2014-28197, PVP2015-45286) we had started to determine the static equivalent pressures pstat of the eight detonative pressure scenarios in long and short pipes for different detonable gas mixtures. The pstat-values are of vital importance for process design: by assigning static equivalent pressures to the highly dynamic detonative pressure peaks it is possible to apply the established pressure vessel guidelines, which can only cope with static loads, for the design of detonation pressure resistant pipes. One important finding was that the ratio R between pstat at the location where transition from deflagration to detonation occurs and pstat in the region of the stable detonation strongly depends on the reactivity of the gas mixture. In this paper we present experimental data showing the variation of R over the entire explosive range of Methane/O2/N2 mixtures. Qualitatively, the results should be representative for all other combustible/O2/N2-mixtures. Furthermore, recommendations for estimating pstat values of short pipe scenarios on basis of the long pipe scenarios are given.
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Verzwyvelt, S. A., and J. Berryman. "The Determination of the Hydrogen Pressure Equivalent of One Amp Hour of Capacity in Nickel Hydrogen Cells." In 27th Intersociety Energy Conversion Engineering Conference (1992). SAE International, 1992. http://dx.doi.org/10.4271/929108.
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Vallet, Christophe, Didier Lasseux, Philippe Sainsot, and Hassan Zahouani. "Numerical Determination of Sealing Performance of a Rough Contact: Real Versus Synthetic Fractal Surfaces." In ASME 2008 Pressure Vessels and Piping Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/pvp2008-61213.
Full textAbstract:
In this work, we adress the issue of sealing performance of metal gaskets using a deterministic approach that allows the analysis of creeping viscous flow and diffusion through a tight contact between rough surfaces taking into account surface deformation. Our analysis is focused on rough surfaces exhibiting fractal properties, and our purpose is to study the validity of the use of synthetic fractal surfaces as a representation of real ones. Two kinds of real surfaces, obtained from two machining processes — lapping and sand-blasting — are considered. After checking the fractal nature of these surfaces, equivalent fractal ones are synthesized. Distributions of contact areas on the one hand, and transport properties K (for viscous flow) and D (for diffusion) on the other, obtained from real and synthetic surfaces are compared for a wide range of tightening. This comparison leads to the conclusion that the fractal representation is adequate to predict mechanical and transport properties of a contact between lapped or sand-blasted surfaces. Finally, using synthetic surfaces, it is shown that sealing performance of a rough contact decreases when the arithmetic roughness Ra and the fractal dimension Df increase.