Academic literature on the topic 'Holding pressure'
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Journal articles on the topic "Holding pressure"
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PALOU, ENRIQUE, AURELIO LÓPEZ-MALO, GUSTAVO V. BARBOSA-CÁNOVAS, JORGE WELTI-CHANES, and BARRY G. SWANSON. "Oscillatory High Hydrostatic Pressure Inactivation of Zygosaccharomyces bailii." Journal of Food Protection 61, no. 9 (September 1, 1998): 1213–15. http://dx.doi.org/10.4315/0362-028x-61.9.1213.
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Zygosaccharomyces bailii inactivation was evaluated in oscillatory high hydrostatic pressure (HHP) treatments at sublethal pressures (207, 241, or 276 MPa) and compared with continuous HHP treatments in laboratory model systems with a water activity (aw) of 0.98 and pH 3.5. The yeast was inoculated into laboratory model systems and subjected to HHP in sterile bags. Two HHP treatments were conducted: continuous (holding times of 5, 10, 15, 20, 30, 60, or 90 min) and oscillatory (two, three, or four cycles with holding times of 5 min and two cycles with holding times of 10 min). Oscillatory pressure treatments increased the effectiveness of HHP processing. For equal holding times, Z. bailii counts decreased as the number of cycles increased. Holding times of 20 min in HHP oscillatory treatments at 276 MPa assured inactivation (<10 CFU/ml) of Z. bailii initial inoculum. Oscillatory pressurization could be useful to decrease Z. bailii inactivation time.
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PAN, HAO, MATTHEW BUENCONSEJO, KARL F. REINEKE, and Y. CAROL SHIEH. "Effect of Process Temperature on Virus Inactivation during High Hydrostatic Pressure Processing of Contaminated Fruit Puree and Juice." Journal of Food Protection 79, no. 9 (September 1, 2016): 1517–26. http://dx.doi.org/10.4315/0362-028x.jfp-16-004.
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ABSTRACT High pressure processing (HPP) can inactivate pathogens and retain fruit qualities. Elevated HPP pressure or time increases virus inactivation, but the effect of temperature is not consistently observed for norovirus and hepatitis A virus. In the present study, the effectiveness of HPP holding temperatures (<40°C) and pressures were evaluated for inactivating surrogates (murine norovirus [MNV] and MS2 coliphage) in pomegranate and strawberry juices and strawberry puree using a 24-liter HPP system. The holding temperature was established by setting the HPP initial temperature via pretrials. All trials were able to arrive at the designated holding pressure and holding temperature simultaneously. MNV inactivation in juices was conducted at 300 MPa for 3 min with various holding temperatures (10 to 30°C). A regression equation was derived, Y = −0.08 × X + 2.6 log PFU, R2 = 0.96, where Y is the log reduction and X is the holding temperature. The equation was used to predict a 2.6-log reduction in juices at 0°C holding temperature and indicated that MNV inactivation was inversely proportional to temperature increase. MNV survival during HPP did not differ significantly in pomegranate and strawberry juices. However, MS2 coliphage inactivation was greater as the holding temperature increased (from 15 to 38°C) at 600 MPa for 3 min. The increased inactivation trend is presumably similar to that for hepatitis A virus, but the holding temperature was not correlated with the reduction of HPP-resistant MS2 in strawberry puree. When the HPP holding pressure was evaluated independently in strawberry puree, a 5-log reduction of MNV was predicted through regression analysis at the holding pressure of 424 MPa for 3 min at 20°C. These parameters should inactivate >5 log PFU of MNV in juices, based upon a greater inactivation in berry juice than in puree (1.16-versus 0.74-log reduction at 300 MPa). This research illustrates use of predictive inactivation and a feasible means for manipulating HPP parameters for effective virus inactivation in fruit juices and puree.
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Whitelaw, W. A., B. McBride, and G. T. Ford. "Effect of lung volume on breath holding." Journal of Applied Physiology 62, no. 5 (May 1, 1987): 1962–69. http://dx.doi.org/10.1152/jappl.1987.62.5.1962.
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The mechanism by which large lung volume lessens the discomfort of breath holding and prolongs breath-hold time was studied by analyzing the pressure waves made by diaphragm contractions during breath holds at various lung volumes. Subjects rebreathed a mixture of 8% CO2–92% O2 and commenced breath holding after reaching an alveolar plateau. At all volumes, regular rhythmic contractions of inspiratory muscles, followed by means of gastric and pleural pressures, increased in amplitude and frequency until the breakpoint. Expiratory muscle activity was more prominent in some subjects than others, and increased through each breath hold. Increasing lung volume caused a delay in onset and a decrease in frequency of contractions with no consistent change in duty cycle and a decline in magnitude of esophageal pressure swings that could be accounted for by force-length and geometric properties. The effect of lung volume on the timing of contractions most resembled that of a chest wall reflex and is consistent with the hypothesis that the contractions are a major source of dyspnea in breath holding.
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Bonner, Stephen J., Graham B. Schaffer, and Ji Yong Yao. "Pressure Assisted Sintering of an Aluminium Alloy." Materials Science Forum 618-619 (April 2009): 627–30. http://dx.doi.org/10.4028/www.scientific.net/msf.618-619.627.
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An aluminium alloy was sintered using a conventional press and sinter process, at various gas pressures, to observe the effect of sintering gas pressure on the densification rate. Compacts of aluminium alloy 2712 (Al-3.8Cu-1Mg-0.7Si-0.1Sn) were prepared from elemental powders and sintered in a horizontal tube furnace under nitrogen or argon at 590°C for up to 60 minutes, and air cooled. The gas flow was adjusted to achieve specific gas pressures in the furnace. It has been found that increasing the nitrogen pressure at the start of the isothermal holding stage to 160kPa increased the densification rate compared to standard atmospheric pressure sintering. Increasing the nitrogen pressure further, up to 600kPa, had no additional benefit. The densification rate was increased significantly by increasing the gas pressure to 600kPa during both heating and isothermal holding. Under argon the elevated pressure did not increase the densification rate. Results seem to suggest that the beneficial effect of the elevated pressure on the rate of densification is related to nitride formation.
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Wang, Shi Quan, Shu Cai Wang, Yi Peng Zhang, and Rong Zhang. "Research on Quick Salting Duck Egg with Pulsed Pressure and Water Cycle Technology." Applied Mechanics and Materials 422 (September 2013): 94–99. http://dx.doi.org/10.4028/www.scientific.net/amm.422.94.
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A pulsed pressure-water cycle technology was applied to accelerate the salting process. Effects of pulse pressure amplitude, high pressure holding time/atmospheric pressure holding time ratio and water cycle acting time on salt contents of duck white and duck yolk were studied by single factor and orthogonal array design methods. The experimental results showed that during the 3 day salting with 24% Salt solution under 30 °C. To obtain optimal quality of salted eggs and the optimum mass transfer rate, solution was obtained under the following conditions: pulse pressure amplitude was 140 kpa and high pressure holding time/ atmospheric pressure holding time ratio was 8:16min, water cycle pulsation ratio was 2:10 min, and the water cycle acting time was 132 min.
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RATPHITAGSANTI, WANNASAWAT, JUHEE AHN, V. M. BALASUBRAMANIAM, and AHMED E. YOUSEF. "Influence of Pressurization Rate and Pressure Pulsing on the Inactivation of Bacillus amyloliquefaciens Spores during Pressure-Assisted Thermal Processing." Journal of Food Protection 72, no. 4 (April 1, 2009): 775–82. http://dx.doi.org/10.4315/0362-028x-72.4.775.
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Pressure-assisted thermal processing (PATP) is an emerging sterilization technology in which a combination of pressure (500 to 700 MPa) and temperature (90 to 120°C) are used to inactivate bacterial spores. The objective of this study was to examine the role of pressurization rate and pressure pulsing in enhancing PATP lethality to the bacterial spore. Bacillus amyloliquefaciens TMW 2.479 spore suspensions were prepared in deionized water at three inoculum levels (1.1 × 109, 1.4 × 108, and 1.3 × 106 CFU/ml), treated at two pressurization rates (18.06 and 3.75 MPa/s), and held at 600 MPa and 105°C for 0, 0.5, 1, 2, 3, and 5 min. Experiments were carried out using custom-fabricated, high-pressure microbial kinetic testing equipment. Single and double pulses with equivalent pressure–holding times (1 to 3 min) were investigated by using the spore suspension containing 1.4 × 108 CFU/ml. Spore survivors were enumerated by pour plating, using Trypticase soy agar after incubation at 32°C for 2 days. During short pressure–holding times (≤2 min), PATP treatment with the slow pressurization rate provided enhanced spore reduction over that of the fast pressurization rate. However, these differences diminished with extended pressure–holding times. After a 5-min pressure–holding time, B. amyloliquefaciens population decreased about 6 log CFU/ml, regardless of pressurization rate and inoculum level. Double-pulse treatment enhanced PATP spore lethality by approximately 2.4 to 4 log CFU/ml, in comparison to single pulse for a given pressure–holding time. In conclusion, pressure pulsing considerably increases the efficacy of PATP treatment against bacterial spores. Contribution of pressurization rate to PATP spore lethality varies with duration of pressure holding.
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Luscher, C., A. Balasa, A. Fröhling, E. Ananta, and D. Knorr. "Effect of High-Pressure-Induced Ice I-to-Ice III Phase Transitions on Inactivation of Listeria innocua in Frozen Suspension." Applied and Environmental Microbiology 70, no. 7 (July 2004): 4021–29. http://dx.doi.org/10.1128/aem.70.7.4021-4029.2004.
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ABSTRACT The inactivation of Listeria innocua BGA 3532 at subzero temperatures and pressures up to 400 MPa in buffer solution was studied to examine the impact of high-pressure treatments on bacteria in frozen matrices. The state of aggregation of water was taken into account. The inactivation was progressing rapidly during pressure holding under liquid conditions, whereas in the ice phases, extended pressure holding times had comparatively little effect. The transient phase change of ice I to other ice polymorphs (ice II or ice III) during pressure cycles above 200 MPa resulted in an inactivation of about 3 log cycles, probably due to the mechanical stress associated with the phase transition. This effect was independent of the applied pressure holding time. Flow cytometric analyses supported the assumption of different mechanisms of inactivation of L. innocua in the liquid phase and ice I (large fraction of sublethally damaged cells due to pressure inactivation) in contrast to cells subjected to ice I-to-ice III phase transitions (complete inactivation due to cell rupture). Possible applications of high-pressure-induced phase transitions include cell disintegration for the recovery of intracellular components and inactivation of microorganisms in frozen food.
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HAYAKAWA, Motoyuki, Shoko AKEMINE, and Yoshirou CHISHIMA. "HighPerformance Holding-Power Measuring System and Evaluation of Holding-Power of Pressure Sensitive Adhesive Tapes." Journal of The Adhesion Society of Japan 37, no. 6 (2001): 224–30. http://dx.doi.org/10.11618/adhesion.37.224.
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Zhu, Lai Yu, Chun Peng Chu, and Bing Yan Jiang. "Research on Warpage of the Microfluidic Chip in Injection Molding Process." Advanced Materials Research 926-930 (May 2014): 345–48. http://dx.doi.org/10.4028/www.scientific.net/amr.926-930.345.
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Reducing volumetric warpage during the injection molding process is a challenging problem in the production of microfluidic chips, as the warpage directly affects the bonding quality of the substrate and the cover sheet. In this study, the injection molding of substrate and the cover sheet, composed of PolymethylMethacrylate(PMMA), was simulated. The effect of different process parameters, holding pressure, holding time, mould temperature and injection speed, were investigated via single factor experiments, observing the warpage of the sheet with Three-Coordinate Measuring Machine. The analysis showed that the warpage was affected by non-uniform shrinkage and residual stress of the melt. Holding pressure and holding time had a greater effect on the warpage than the mould temperature and injection speed did. Therefore, reasonable holding pressure and holding time can effectively reduce the warpage of microfluidic chips in the injection molding process.
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Lyamina, N. P., S. V. Lyamina, V. N. Senchikhin, F. Н. Downey, E. B. Manukhina, M. L. Smith, and C. F. Kneip. "Predictive value of breath-holding pressure response as a new diagnostic test for latent arterial hypertension detection." "Arterial’naya Gipertenziya" ("Arterial Hypertension") 17, no. 4 (August 28, 2011): 337–41. http://dx.doi.org/10.18705/1607-419x-2011-17-4-337-341.
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Background. Latent arterial hypertension (LAH) is a serious health problem and is often underdiagnosed in routine examination. Thus, a sensitive and economical test to detect latent hypertension is needed. Objective. To assess the opportunity of pressure response to voluntary breath holding (30 second breath holding test) to detect masked arterial hypertension in young subjects. Design and methods. 269 young subjects (18-36 years old) with no clinical signs of cardiovascular disease, diabetes mellitus, any chronic diseases including pulmonary diseases, who did not do sports professionally, underwent 30 second breath holding test. Results. The results of breath holding and 24 hour monitoring tests coincided in 250 out of 269 cases (93 %). Latent hypertensions was diagnosed (by 24 hour blood pressure monitoring) in none of the subjects with normal or high normal resting blood pressure and negative breath holding test (negative predictive value - 100 %). For subjects with normal or high normal resting blood pressure, a positive breath holding test (53 subjects) detected latent arterial hypertension in 34 subjects (positive predictive value - 64 %). Conclusions. The breath holding test helps to effectively exclude latent arterial hypertension in healthy subjects and accurately identifies subjects who should be further tested for arterial hypertension.
Dissertations / Theses on the topic "Holding pressure"
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Khamzin, Yersin. "Technologie vstřikování zkušebních těles z termoplastů." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2021. http://www.nusl.cz/ntk/nusl-444217.
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The diploma thesis focuses on the optimization of technological parameters of plastic injection molding and the study of the influence of technological parameters on the quality of molded test specimens’ type 1A. The quality of molded parts for 3 types of polypropylene (PP) with different melt flow rate (Mosten GB 002, Mosten GB 218, Mosten MA 230) and 1 type of polystyrene (PS) (Krasten PS GP 154) was evaluated in terms of dimensional stability and weight. The contribution of software for modeling the plastic injection molding process was evaluated in this work. SOLIDWORKS Plastics software was used to optimize technological parameters. The construction of the bodies, mold and cooling system was constructed, and test bodies were produced on the basis of parameters obtained from the simulation of the injection molding process. Their quality parameters were compared with a 3D model and for each of the studied materials the optimal technological parameters were selected in terms of quality and the degree of influence of individual injection parameters on the quality of moldings was evaluated. The accordance of the results of the theoretical simulation with the real experiment was proved and a computational module independent of the optimized quality parameters, generally suitable for optimizing the quality parameters of the injected parts, was developed.
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Ribeiro, Ana Teresa da Cunha Machado. "Desenvolvimento de fiambres de pescado com utilização de fibras vegetais e aplicação de diferentes tecnologias de gelificação." Doctoral thesis, Universidade de Évora, 2020. http://hdl.handle.net/10174/27679.
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Com o objetivo de desenvolver um produto saudável e pronto a consumir com
características semelhantes às de um fiambre de porco, entre as quais a textura, prepararamse
fiambres de pescado com incorporação de fibras vegetais e aplicação de duas tecnologias
de gelificação.
Neste sentido, foi estudado o efeito da espécie (dourada, robalo e corvina, de
aquacultura), época de captura (verão e inverno), adição de transglutaminase microbiana
(MTGase) e glucomanano de konjac (KGM) e gelificação térmica (pasteurização) ou
processamento por altas pressões (HPP), nas propriedades texturais e na cor dos fiambres. O
produto preparado com corvina capturada no inverno e 0,5 % de MTGase apresentou as
características que mais se assemelhavam às do fiambre de porco. A substituição de KGM por
fibra de chicória e a adição de isolado de proteína de ervilha permitiram otimizar as
propriedades físicas e melhorar as propriedades funcionais deste fiambre.
A preferência do consumidor, relativamente à cor de fiambre de peixe e avaliada por um
inquérito “on line”, foi para um fiambre preparado com 0,0005 % de cochonilha, cuja cor era
muito semelhante à do fiambre de corvina sem corante.
Os fiambres de corvina submetidos às combinações 350 MPa/10 min ou 20 min/30 °C e
500 MPa/10 min/30 °C apresentaram a textura mais próxima da do fiambre pasteurizado. Sob
estas últimas condições de HPP, estudou-se o efeito da MTGase (0,25 % - 0,5 %) como
potenciador da gelificação, tendo os resultados evidenciado a necessidade do uso de, pelo
menos, 0,25 % de MTGase, para não comprometer as propriedades texturais.
O tratamento térmico foi mais eficaz na inativação microbiana que o HPP a 500 MPa/10
min/30 °C, e os fiambres, pasteurizados ou submetidos ao HPP, apresentaram-se próprios para
consumo até ao 35.º e 21.º dia de armazenagem em refrigeração, respetivamente; ABSTRACT:
In order to develop a healthy and ready to eat product with similar characteristics to
those of a commercial cooked pork ham, namely texture, fish hams were prepared with the
incorporation of vegetable fibers and the application of two gelation technologies.
Thus, the effect of the species (farmed gilthead sea bream, sea bass and meagre),
harvesting seasons (summer and winter), addition of microbial transglutaminase (MTGase) and
konjac glucomannan (KGM), as well as thermal gelation (pasteurization) or high pressure
processing (HPP), were studied on the textural properties and color of fish ham. The
characteristics of the ham prepared with winter meagre and 0.5% MTGase were the most
similar to those of cooked pork ham. The replacement of KGM by chicory fiber and the
addition of pea protein isolate allowed to optimize the physical properties and to improve the
functional properties of this ham.
Consumer preference for fish ham color an assessed by an on-line survey was for a ham
prepared with 0.0005% cochineal, whose color was very similar to that of the dye-free meagre.
The meagre hams submitted to the combinations 350 MPa/10 min or 20 min/30 °C and
500 MPa/10 min/30 °C had a texture closer to that of pasteurized ham. Under these HPP
conditions, the effect of MTGase (0.25 % - 0.5 %) as a gelation enhancer was studied, and the
results showed that at least 0.25 % MTGase is needed, for not compromising the textural
properties.
The heat treatment was more effective on the microbial inactivation than HPP at 500
MPa/10 min/30 °C, and the pasteurized or HPP cooked hams were fit for consumption up to
the 35th and 21st storage days in refrigeration, respectively.
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Bulejko, Pavel. "Application of Polymeric Hollow-Fiber Membranes in Air Filtration." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-401603.
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Membrány z dutých vláken jsou široce využívány v aplikacích týkajících se úpravy kapalin jako např. při čištění odpadních vod, v membránových kontaktorech a bioreaktorech, membránové destilaci apod. I když jsou často využívány při separacích směsí plynů, je jejich použití pro mechanickou filtraci aerosolů velmi vzácné. Tato práce se zabývá filtrací vzduchu pomocí polypropylenových membrán z dutých vláken včetně jejich filtrační účinnosti, tlakových ztrát a také zanášením při dlouhodobé filtraci. Filtrační účinnost byla proměřena za použití různých aerosolů jako TiO2 a síran amonný. Tlakové ztráty byly měřeny při různých konfiguracích, tj. různé filtrační ploše a průměru vlákna membrány. Zanášení membrán bylo testováno použitím normovaného prachu definovaného normou ANSI/ASHRAE 52.2. Predikční modely pro filtrační účinnost a permeabilitu/tlakovou ztrátu membrány byly aplikovány na parametry membrán z dutých vláken a porovnány. Tyto membrány mají velikost pórů kolem 90 nm a poměrně nízkou porositu a tím vysoký potenciál pro separaci nanočástic ze vzduchu. Dále byla provedena analýza filtračního koláče a vyhodnocení energetických nároků a porovnány s teoretickými modely. V závěru práce je nastíněn odhad ceny životního cyklu při filtraci pomocí těchto membrán.
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Linhart, Rasmus, and Daniel Nyborg. "Adapt or die : A qualitative study on how institutional pressures influence the strategies of sustainable investors and their holdings." Thesis, Uppsala universitet, Företagsekonomiska institutionen, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-446936.
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Large institutional actors in the financial arena are moving their capital in a sustainable direction. This implies a change of the institutional norms and rules regarding sustainable investing. One of the problematic aspects of sustainable investing is how investors use different strategies to influence their holdings and what implications this choice might have on a sector level. The purpose of this paper is to empirically examine how the strategies from institutional investors are an expression of the current norms and rules in the field of sustainable investing. It also intends to illustrate how institutional pressures influence the strategies of investors and their holdings. By interviewing respondents from eleven institutional investors, we present data regarding norms and rules for sustainable investing and the consequences of the investor’s strategies. Our findings indicate there has been an immense increase in demand for sustainable products in recent years, resulting in institutional pressures that have influenced both the investors and their holdings. This exposes the field to selection processes which may force organizations to the point of adapt or die. Finally, our conclusion provides practical implications on what role institutional investors have in the quest for sustainable development.
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Yang, Chih-Yuan, and 楊智元. "Improvement on Holding Pressure of All-Electric Injection Molding Machine." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/29644098262385392413.
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碩士國立中央大學
機械工程研究所
92
If we talk about the plastic, most people will have an impression on the injection molding machine in the modern society. It is the fastest, most convenient and popular machine to manufacture the plastic products. From the industrial use to people’s daily use, most plastic products are manufactured by the injection molding machine. The quality of the product has relations with the accuracy of the controller. The injection molding technology has already developed for so many years. Whether the all-electric or hydraulic machinery, the performance is up to the standard. Nowadays the major problem about the injection molding machine is tracking the holding pressure profile. The holding pressure profile relates to the quality of the product a lot. In this paper, I use the fuzzy and the PID control law are used and compared to track the pressure profile.
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Su, Heng-Yi, and 蘇恆毅. "Improvement of Injection Molded Parts Appearance Using Gas-Assisted Holding Pressure." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/12304944644168675263.
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碩士國立高雄第一科技大學
機械與自動化工程研究所
101
Weld lines and sink mark are two surface defects that commonly appear along injection molded parts. Particularly, slight shrinkage lines that cause uncertain visual darkness depending on watching angles, is also named as ghost mark. The study aims to investigate the causes of these two surface defects with a tensile-testing-sample mold and improve them by using an exterior gas-assisted holding pressure method. The injection mold is peculiarly designed to enable the control of exterior pressure at the area of weld lines which is happened at the filling end of melt plastics. The surface qualities of testing samples are digitally examined through a proposed image processing approach. Experimental results depict that ghost mark can be easily found close to the area of weld lines, and the setting of high mold and melt temperatures and high injection speed and pressure enables to reduce the defect. Moreover, employing exterior gas-assisted holding pressure on the defect surface can efficiently improve its qualities; especially using an air pressure above 30 kgf/cm2 has significant effect on reducing ghost mark appeared on the surface of injection molded parts.
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Chen, Jen-Te, and 陳仁德. "A Study on the Holding Pressure & Feeding Back-Pressure Control for Hydraulic Plastic Injection Molding Machine." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/s8x8eb.
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碩士國立高雄第一科技大學
電機工程研究所碩士班
105
In the injection molding process, the injection pressure, the injection velocity, the injection temperature, the clamping force, the feeding quantity and other factors will have influence on the quality of the injection molding. In order to study the complicated forming characteristics, firstly, we establish the molding process model to understand the dynamic behavior of the plastic injection molding operation. The established model can be further verified with the real machine to ensure the control design. In this research, we study the control performance of the injection-holding transition, holding pressure and the feeding back-pressure. Based on those studies some improving methods were proposed. For the injection-holding transition control, the injection screw position is decelerated before the injection ending point, and when the pressure turns flat the system switch to pressure control loop with S-curve smoothly changing the pressure to the first section holding pressure. For the holding pressure control, constant pressure with precise time period was controlled for the first section pressure control to make the mold precisely packed. After that, a smoothly declined holding pressure control was proposed to prevent the plastics flow in/out of the mold during the cooling stage. For the feeding back pressure control, the injection hydraulic cylinder continues to maintain back pressure, and the feeding motor rises the speed to the set value with S-curve and maintains constant speed thereafter. When the injection hydraulic cylinder reaches to the point before the end feeding position with a certain distance, the feeding motor decelerates to the minimum speed linearly according to the distance to the end feeding position. Finally, when the injection hydraulic cylinder reaches the end feeding position, the feeding motor stops immediately. At this point, the injection hydraulic cylinder will maintain the back pressure, and it will be stopped precisely at the end feeding position. Keyword: injection-holding transition, smoothly declined holding pressure, feeding back-pressure
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鐘啟榮. "Study of Quality Assurance Contorl Failure Rate for Holding Pressure Gas Pipeline." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/95049147492692130020.
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Lee, I.-Pin, and 李義評. "Fuzzy Control Injection Velocity and Holding Pressure of an Injection Molding Machine." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/95242599764628454060.
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碩士國立成功大學
機械工程研究所
84
The most important three processes of injection engineering of IMM(injection molding machine) are holding,sprue -closing and cooling,which notablly affect the quality of products.In order to get precise shape,mold shape change and material solidifying need to be considered before injection process.By way of multi- state injection,we can effectively adjust injection speed depending on thickness,shape and projective area of products. And,the multi-holding pressure method could be used to prevent the shrink fault and ineer stress problem of products.Because of the nonlinear time- varying characteristics of IMM cause by complex system structure and change of the oil''s viscosity due to the various temperatures,it is very difficult to get accurate mathematical transfer function.And,all of this increases the difficultly in control.Because the fuzzy control method is to emulate the mankind''s decision process it does not need to get the mathematical model of IMM.And,we can design controller directly. When we design fuzzy controller,it is necessary to adjust parameters.The traditional method to obtain optimum parameters is trial and error.But time-consuming and lack of systematization are its big drawbacks.Taguchi method could easily obtain optimum parameters in least experiments by way of systematic reasoning. Because liquid plastic is so viscous that the signals from linear scale irregularly vary.If we differentiate these signals we will get much undesirable noise.The velocity estimator could help us to improve this problem.Three kinds of estimators are Taylor series expansion, backward difference equation,and least square method.Among them, the least square method is the most powerful filter so we use it to eliminate the effect of noise in this experiment.
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Hou, Shang-Chieh, and 侯尚杰. "Study on thermal properties, holding pressure and dynamic of solvent debinding in alumina injection molding." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/93735875928760550836.
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碩士國立臺灣大學
材料科學與工程學研究所
85
AbstractThe effects of holding pressure (PIII) and holding time (tIII) on the properties of injection molding parts were investigated. Besides, gate pressure and cavity pressure were monitored by pressure sensors positioned in front of and inside of the gate. Three polymeric additives, paraffin wax, polypropylene, stearic acid, and alumina feedstocks with former polymeric additives, in a solid loading containing 56.6 vol%, were studied by thermogravimetric analysis in air. In addition, weight loss, pore size distribution and dilatometry of test bars were measured during solvent debinding.Increasing holding pressure from 5% to 95% and holding time up to 75 sec, the pressure-time traces showed different tendency in the mold. Maximum pressure occurred at the end of pressure build-up. Increasing the holding pressure (PIII), 5% to 95%, raised the gate pressure and cavity pressure. Because of resistance through the gate, the cavity pressure was slightly smaller than the gate pressure. The mass, dimensions and flatness of injection molded were measured, and would increased as holding pressure. A high holding pressure(≧50%) would also decrease the sink of specimens, and prolonged the packing time by increasing holding time. Green bulk density, fired density and four-point bending fracture strength were obtained. The results showed that there was not apparent dependence of green bulk density, fired density and fracture strength on the injection pressure(PIII) .N-heptane was used to leach soluble polymers in solvent debinding. The weight of sample measurements decreased with time was measured by two methods, either interruption and in-situ time methods. The temperature effects of n-heptane tested from 40oC to 60oC, the result showed that the case of 60oC exhibited a fast leaching rate and a maximum swelling ratio measured by a laser dilatometer. Pore size of debinding specimens were measured by a mercury porosimeter, and showed a bimodal distribution, but increased the pore volume as the debinding time proceeded.TGA at a heating rate from 2 oC/min to 20 oC/min of polymeric additives and alumina greens were conducted up to 550 oC in purged air 50ml/min. The TGA curves of polymeric additives and feedstocks shifted to low temperature as the heating rate decreased. Then, the activated energy and reaction order were analyzed using Ozawa and Friedman, methods. The activated energy was in range 90?0 kJ/mol, but the reaction order of alumina green parts changed from 0 to 3.2 in the later stage of the thermal debinding of alumina feedstocks. Keywords：alumina, injection molding, pressure, solvent debinding, reaction order, thermal debinding.
Books on the topic "Holding pressure"
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The catcher in the rye: Innocence under pressure. New York: Twayne Publishers, 1993.
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Pinsker, Sanford. The catcher in the rye: Innocence under pressure. New York: Twayne Publishers, 1993.
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Muders, Thomas, and Christian Putensen. Pressure-controlled mechanical ventilation. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199600830.003.0096.
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Beside reduction in tidal volume limiting peak airway pressure minimizes the risk for ventilator-associated-lung-injury in patients with acute respiratory distress syndrome. Pressure-controlled, time-cycled ventilation (PCV) enables the physician to keep airway pressures under strict limits by presetting inspiratory and expiratory pressures, and cycle times. PCV results in a square-waved airway pressure and a decelerating inspiratory gas flow holding the alveoli inflated for the preset time. Preset pressures and cycle times, and respiratory system mechanics affect alveolar and intrinsic positive end-expiratory (PEEPi) pressures, tidal volume, total minute, and alveolar ventilation. When compared with flow-controlled, time-cycled (‘volume-controlled’) ventilation, PCV results in reduced peak airway pressures, but higher mean airway. Homogeneity of regional peak alveolar pressure distribution within the lung is improved. However, no consistent data exist, showing PCV to improve patient outcome. During inverse ratio ventilation (IRV) elongation of inspiratory time increases mean airway pressure and enables full lung inflation, whereas shortening expiratory time causes incomplete lung emptying and increased PEEPi. Both mechanisms increase mean alveolar and transpulmonary pressures, and may thereby improve lung recruitment and gas exchange. However, when compared with conventional mechanical ventilation using an increased external PEEP to reach the same magnitude of total PEEP as that produced intrinsically by IRV, IRV has no advantage. Airway pressure release ventilation (APRV) provides a PCV-like squared pressure pattern by time-cycled switches between two continuous positive airway pressure levels, while allowing unrestricted spontaneous breathing in any ventilatory phase. Maintaining spontaneous breathing with APRV is associated with recruitment and improved ventilation of dependent lung areas, improved ventilation-perfusion matching, cardiac output, oxygenation, and oxygen delivery, whereas need for sedation, vasopressors, and inotropic agents and duration of ventilator support decreases.
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Jacquet, Jennifer. Guilt and Shame in U.S. Climate Change Communication. Oxford University Press, 2017. http://dx.doi.org/10.1093/acrefore/9780190228620.013.575.
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Some of the major misconceptions in the United States about climate change—such as the focus on scientific uncertainty, the “debate” over whether climate change is caused by humans, and pushback about how severe the consequences might be—can be seen as communications battles. An interesting area within communications is the contrasting use of guilt and shame for climate-related issues. Guilt and shame are social emotions (along with embarrassment, pride, and others), but guilt and shame are also distinct tools. On the one hand, guilt regulates personal behavior, and because it requires a conscience, guilt can be used only against individuals. Shame, on the other hand, can be used against both individuals and groups by calling their behavior out to an audience. Shaming allows citizens to express criticism and social sanctions, attempting to change behavior through social pressure, often because the formal legal system is not holding transgressors accountable. Through the use of guilt and shame we can see manifestations of how we perceive the problem of climate change and who is responsible for it. For instance, in October 2008, Chevron, one of the world’s largest fossil fuel companies, placed advertisements around Washington, DC, public transit stops featuring wholesome-looking, human faces with captions such as “I will unplug things more,” “I will use less energy,” and “I will take my golf clubs out of the trunk.” Six months later, DC activists reworked the slogans by adding to each the phrase “while Chevron pollutes.” This case of corporate advertising and subsequent “adbusting” illustrates the contrast between guilt and shame in climate change communication. Guilt has tended to align with the individualization of responsibility for climate change and has been primarily deployed over issues of climate-related consumption rather than other forms of behavior, such as failure to engage politically. Shame has been used, largely by civil society groups, as a primary tactic against fossil fuel producers, peddlers of climate denial, and industry-backed politicians.
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Hopke, Jill E., and Luis E. Hestres. Communicating about Fossil Fuel Divestment. Oxford University Press, 2017. http://dx.doi.org/10.1093/acrefore/9780190228620.013.566.
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Divestment is a socially responsible investing tactic to remove assets from a sector or industry based on moral objections to its business practices. It has historical roots in the anti-apartheid movement in South Africa. The early-21st-century fossil fuel divestment movement began with climate activist and 350.org co-founder Bill McKibben’s Rolling Stone article, “Global Warming’s Terrifying New Math.” McKibben’s argument centers on three numbers. The first is 2°C, the international target for limiting global warming that was agreed upon at the United Nations Framework Convention on Climate Change 2009 Copenhagen conference of parties (COP). The second is 565 Gigatons, the estimated upper limit of carbon dioxide that the world population can put into the atmosphere and reasonably expect to stay below 2°C. The third number is 2,795 Gigatons, which is the amount of proven fossil fuel reserves. That the amount of proven reserves is five times that which is allowable within the 2°C limit forms the basis for calls to divest.The aggregation of individual divestment campaigns constitutes a movement with shared goals. Divestment can also function as “tactic” to indirectly apply pressure to targets of a movement, such as in the case of the movement to stop the Dakota Access Pipeline in the United States. Since 2012, the fossil fuel divestment movement has been gaining traction, first in the United States and United Kingdom, with student-led organizing focused on pressuring universities to divest endowment assets on moral grounds.In partnership with 350.org, The Guardian launched its Keep it in the Ground campaign in March 2015 at the behest of outgoing editor-in-chief Alan Rusbridger. Within its first year, the digital campaign garnered support from more than a quarter-million online petitioners and won a “campaign of the year” award in the Press Gazette’s British Journalism Awards. Since the launch of The Guardian’s campaign, “keep it in the ground” has become a dominant frame used by fossil fuel divestment activists.Divestment campaigns seek to stigmatize the fossil fuel industry. The rationale for divestment rests on the idea that fossil fuel companies are financially valued based on their resource reserves and will not be able to extract these reserves with a 2°C or lower climate target. Thus, their valuation will be reduced and the financial holdings become “stranded assets.” Critics of divestment have cited the costs and risks to institutional endowments that divestment would entail, arguing that to divest would go against their fiduciary responsibility. Critics have also argued that divesting from fossil fuel assets would have little or no impact on the industry. Some higher education institutions, including Princeton and Harvard, have objected to divestment as a politicization of their endowments. Divestment advocates have responded to this concern by pointing out that not divesting is not a politically neutral act—it is, in fact, choosing the side of fossil fuel corporations.
Book chapters on the topic "Holding pressure"
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Liu, Shanguang, Chuanbiao Luo, Guoai Li, Zheng Lu, and Shenglong Dai. "Healing of Double Oxide Film Defect Under Holding Pressure in A357 Alloy." In High Performance Structural Materials, 289–95. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-13-0104-9_30.
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Wang, Xiaona, Fangwu Ma, Qiang Liu, and Fuquan Zhao. "Research on Holding Pressure and Cooling Process During Hot Forming of Ultra-High Strength Steel 22MnB5." In Lecture Notes in Electrical Engineering, 123–31. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-33747-5_12.
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"Analytic holding under pressure." In On Learning from the Patient, 151–61. Routledge, 2013. http://dx.doi.org/10.4324/9781315879468-16.
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Atkinson, Lucy, Andrew Blick, and Matt Qvortrup. "Pressure and experimentation." In The Referendum in Britain, 74–132. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198823612.003.0003.
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Chapter 2 covers 1945–1979, a period during which referendums progressed from being relatively neglected as a concept in Britain to actually being deployed. Between 1945 and the early 1970s, the idea of holding a major referendum was absent from the forefront of the UK political agenda. But as we will see, the proposition simmered and revived over time. Then between 1973 and 1979, four such votes took place: on the constitutional status of Northern Ireland (1973); on whether or not the UK should continue to participate in the European Community (or ‘Common Market’, in 1975); and on whether or not devolution should be implemented in Scotland and Wales (both 1979). The chapter considers why referendums occurred, and their implications for British politics and for the British constitution.
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Richardson, Jeremy. ": Pressure Groups and Parties." In The British Study of Politics in the Twentieth Century. British Academy, 2003. http://dx.doi.org/10.5871/bacad/9780197262948.003.0007.
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The central paradox in reviewing the contribution of British political scientists to the understanding of these intermediary institutions is that both the number of scholars and the output have been considerable, yet the international impact has been relatively modest. Two explanations seem plausible. First, with a few notable exceptions, the centre of gravity of these studies has coincided with the centre of gravity of British political science as a whole – it is largely atheoretical in its research style. A second possible explanation is that studies in these fields have tended to focus on activities (of groups and social movements) or on office-holding (parties) and have been much less interested in power as a concept. Relatively little is known about the effects that this activity has on outcomes in terms of public policy or the distribution of power in society.
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Wada, S., and Y. Ogawa. "High Pressure Effects on Fish Lipid Degradation: Myoglobin Change and Water Holding Capacity." In High Pressure Bioscience and Biotechnology, Proceedings of the International Conference on High Pressure Bioscience and Biotechnology, 351–56. Elsevier, 1996. http://dx.doi.org/10.1016/s0921-0423(06)80059-6.
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Hentati, Fatma, and Neila Masmoudi. "Influence of Injection Molding Parameters on the Mechanical Properties of Injected PC/ABS Parts." In Robust Design Methods [Working Title]. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.95089.
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This study optimized the influence of process parameters on the mechanical properties during injection molding (IM) of PC/ABS blend. The Taguchi method of design of experiments (DOE) was employed to optimize the process parameters and to increase the tensile strength and the elasticity module. Taguchi’s L9 (34) orthogonal array design was employed for the experimental plan. Process parameters of the injection molding such as material temperature, injection pressure, holding time, and mold temperature were studied with three levels. The Signal to noise (S/N) ratio for mechanical properties of PC/ABS blend using the Taguchi method was calculated. Taguchi’s results proposed two sets of optimal injection parameters conditions to achieve the best mechanical characteristics (σ, E). The (S/N) ratio results proved that the injection pressure was the more prominent than the other IM process parameters for the tensile strength, and the material temperature was the more prominent for the elasticity module.
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White, G. Edward. "The American Legal Academy and Jurisprudence II." In Law in American History, Volume III, 346–99. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780190634940.003.0007.
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By the close of World War II, Legal Realism had become the dominant jurisprudential perspective in the American legal academy. But developments connected to the use of totalitarian regimes of the left and right put pressure on the apparent claim of realists that “law” was simply the decisions of officials holding power. In response to that concern, and to the “antidemocratic” dimensions of judicial review of major institutions by unelected judges, “process theory,” featuring emphasis on institutional constraints and the obligation of judges to describe cases on legal principles transcending results in cases, became entrenched as a jurisprudential perspective. But then, between the 1970s and the close of the century, process theory lost its resonance. The chapter surveys those developments.
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Purves, Alex C. "Reaching." In Homer and the Poetics of Gesture, 153–80. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780190857929.003.0006.
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This chapter examines Priam’s gesture of reaching Achilles’ hands to his mouth when he comes to ransom the body of his son. The gesture has been noted for its emotional effect, but here it is framed within the context of other gestures at work in the Iliad’s final book. The chapter draws on Agamben’s definition of gesture as a “bearing” of the body in order to highlight the essential ambiguity of whose hands reach toward whom in the famous scene of supplication. Priam’s desire to lift the body of Hector and Achilles’ dragging of the corpse are both physical forms of expression for bearing up under the pressure of grief. But Achilles’ action speaks also to the drag of gesture itself: its slow undertow, even its clumsiness, as manifested in the various iterations of holding and reaching that Priam and Achilles together attempt to perform.
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Reiter, Walter S. "The Inner Life of Sound." In The Baroque Violin & Viola, 74–84. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780190922696.003.0009.
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One essential element of musical expression is the living sound, capable of holding the constant attention of the audience. This lesson traces that ubiquitous concept from Caccini’s “swelling and abating of the voice” (1602) to the violin études of Mazas (1843). In the Baroque sound world, free from the all-pervasive vibrato of modern times, it was the responsibility of the bow to provide this ‘inner life of sound.’ Based mainly on the writings of Tartini, Geminiani, and Leopold Mozart, all of whom are quoted, this lesson contains five exercises for perfecting the expressive device that guaranteed this living sound, the “Messa di voce.” The many different aspects of its technique, gleaned from the sources, are isolated and explained in detail, from simple pressure with the forefinger to the addition of vibrato: two composers who indicated this device in their compositions, Veracini and Piani, are quoted and illustrated.
Conference papers on the topic "Holding pressure"
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Kubushiro, Keiji, Hiroki Yoshizawa, Takuya Itou, and Hirokatsu Nakagawa. "Creep-Fatigue Properties of the Candidate Materials of 700°C-USC Boiler." In ASME 2007 Pressure Vessels and Piping Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/creep2007-26568.
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Creep-fatigue properties of candidate materials of 700°C-USC boiler are investigated. The candidate materials are Alloy 230, Alloy 263, Alloy 617 and HR6W. Creep-fatigue tests were conducted at 700°C and the effect of both strain range and hold time were studied. Experimental results showed that at 1.0% strain range, cycles to failure with 60 min strain holding is about 10% of that without strain holding, but at 0.7% strain range, cycles to failure with 60 min strain holding decreases down to about 1% of without strain holding. It appears that cycles to failure is decreased by increasing strain holding time at all tested strain ranges, and the effect of holding time is emphasized at small strain range. These phenomena depend on the kind of alloys.
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Bourniquel, Julien, Didier Lasseux, and Jean-François Rit. "Sealing Properties of Joints Between Metal Surfaces Holding Wavy Defects." In ASME 2016 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/pvp2016-63158.
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Internal sealing of many power plant valves is performed by a metal to metal contact, compatible with severe pressure and temperature conditions of liquid water flow. Contact surfaces are treated by hard alloy coating and lapping in order to enhance sealing properties. However, wavy deformation may occur on the surface because of stress induced during manufacturing and all through the device life, for example as a consequence of thermal shocks. We aim to quantitatively correlate the leakage which results from wavy defects through experimental measurements and predictions obtained from modeling. In order to leave as few uncontrolled parameters as possible, the sealing joint is isolated from the valve device as a separate system consisting of a flat and rigid plug and an annular seat holding a wavy defect. The leak sealing properties of the metal to metal contact are expressed by a transmissivity value. This physical quantity has a length cube dimension and relates flow rate to pressure difference by a linear relation. It is intrinsic to the interstitial geometry. The experimental section of this paper relies on two key steps. First, a sample seat, holding a controlled wavy defect, is manufactured. This is achieved by elastically deforming a cylindrical metal part having a tube shape in a lathe’s mandrel. The end-face is machined, lapped and finally the part is released, leaving a wavy defect on the end-face as a consequence of elastic relaxation. Secondly, the transmissivity of the sample seat, pressed against a flat, rigid plug, is determined from leak rate and fluid pressure measurements carried out on specific experimental devices. The procedure is repeated for several clamping loads yielding the transmissivity to apparent contact pressure dependence. In the modeling section, leakage is calculated following three successive main stages. In the whole procedure, the flow action on the structure is neglected. First a geometrical model of the seat holding the manufactured wavy defect is built using a linear modal decomposition on a basis of vibrational eigen modes allowing to represent any kind of defect. Secondly, the remaining open space -i.e. the opening between the plug and seat surfaces-resulting from the clamping force normal to the mean plane of the contact, is computed. A finite element model is used to solve the contact problem on the non-trivial form of the wavy defect on the whole 3D geometry. Finally, the transmissivity is computed by solving the Reynolds equation for incompressible flow within the percolating opening between the plug and the seat. The final result of the modeling section is a transmissivity function of the apparent contact pressure, characterizing the leakage of the given wavy defect on the seat. Predictions of the transmissivity reveal to be in good agreement with that obtained experimentally at low clamping forces and overestimate the leakage for larger ones.
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Lee, Hyeon Bae, Ho-Sub Kim, Junjie Chen, Changheui Jang, Tae Soon Kim, Gary L. Stevens, and Kawaljit Ahluwalia. "Environmentally-Assisted Fatigue Behavior of 316 Stainless Steels in Simulated PWR Primary Environment: Strain Holding, Zn-Addition, and Their Combined Effect." In ASME 2019 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/pvp2019-93134.
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Abstract Low cycle fatigue (LCF) tests of type 316 stainless steel (SS) were conducted in simulated pressurized water reactor (PWR) environments to evaluate the effect of zinc (Zn) content and peak strain holding. The LCF lives of 316 SS increased about 2 to 3 times in PWR environments with Zn addition and peak strain holding (Zn-PWRhold condition). Their combined effect was investigated by using cyclic hardening behavior, dislocation structure analysis, and oxide layer observation. The cyclic behavior in Zn-PWRhold condition showed general primary hardening behavior but quite longer softening behavior than other test conditions. Also, the dislocation density was decreased with Zn addition and increased again with peak strain holding. The Zn penetrates into the oxide layer at the crack tip and modifies the oxide characteristics, which results in improvement of corrosion resistance.
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Higuchi, Makoto, Katsumi Sakaguchi, and Yuichiro Nomura. "Effects of Strain Holding and Continuously Changing Strain Rate on Fatigue Life Reduction of Structural Materials in Simulated LWR Water." In ASME 2007 Pressure Vessels and Piping Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/pvp2007-26101.
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The fatigue life reduces remarkably with reduction in strain rate in simulated light water reactor (LWR) water but the effects of strain wave form on this reduction are still not clear. This paper provides fatigue life data obtained from stepwise strain rate change tests, sine wave tests and strain holding tests. The effects of varying strain rate on fatigue life reduction can be estimated very well by the modified rate approach (MRA) method in the case of the step wise strain rate changing as shown in authors’ previous papers [1, 2, 3, 4, 5]. In the case of sine wave, however, the fatigue life reduction is much less compared to that predicted by the MRA method. The mechanism of such difference is not clear and the quantitative assessment of the fatigue life reduction caused by irregular strain wave form in actual transient seems impossible. The current MRA method gives always conservative assessment for sine wave straining and thus it is judged that this method need not be revised any more. The fatigue life reduction caused by strain holding at the peak of straining cycle in simulated BWR water had been reported in the previous paper [6]. In actual thermal transients, however, strain is not usually held at the peak of straining cycle but at the point somewhat reduced from the peak after the stabilization of temperature. In considering this phenomenon, additional fatigue tests in which the strain was held at the point somewhat reduced from the peak were carried out. In such conditions, the fatigue life reduction caused by strain holding disappeared. The similar fatigue tests with peak strain holding were also carried out in simulated PWR water and no fatigue life reduction can be observed. Considering the effects of strain holding on fatigue, the model for evaluating fatigue life reduction in LWR water was revised.
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Kanno, Takahiro, Norihiko Ito, and Kenji Kawashima. "A cornea holding device for transplantation surgery using negative pressure." In 2017 IEEE Conference on Control Technology and Applications (CCTA). IEEE, 2017. http://dx.doi.org/10.1109/ccta.2017.8062547.
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Asada, Seiji, Yuichi Fukuta, Kawaljit Ahluwalia, and David Steininger. "Study on Effects of Non-Isothermal Condition and Strain Holding on Environmentally Assisted Fatigue in PWR Primary Water Environment." In ASME 2016 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/pvp2016-63798.
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To understand the fatigue behavior of austenitic stainless steels in a simulated PWR primary water environment, the patterns were studied. Austenitic stainless steel Type 316 plate was used as the test material. Regarding non-isothermal testing: isothermal and non-isothermal fatigue tests were carried out for several patterns of temperature change and strain rate change. Typically, fatigue lives for non-isothermal tests with an out-of-phase strain change pattern were longer than those for isothermal tests. Regarding strain holding testing: multiple groups of strain range cycles were separated by a long hold time and several test cases were carried out. Testing shows there is little difference in fatigue life for strain holding tests with high strain amplitude.
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Kang, Yongjoon, Seung-Gun Lee, Gi-Dong Kim, Sang-Hoon Lee, Sang-Woo Song, and Sung-Sik Kang. "Effect of Simulated Post-Weld Heat Treatment on the Mechanical Properties and Microstructure of P-No. 1 Carbon Steels." In ASME 2018 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/pvp2018-84605.
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The effect of simulated post-weld heat treatment (PWHT) on the mechanical properties and microstructure of P-No. 1 materials was investigated and the suitability of the exemption requirements of simulated PWHT as specified in ASME Section III Division 1 Subsection NX-2211 was evaluated. SA-516 Gr. 60 and 70 carbon steel plates and SA-106 Gr. B carbon steel pipe were employed, and the materials were subjected to the simulated PWHT with holding temperatures of 610, 650, 690, and 730 °C for 8 hours. Both the tensile strength and lateral expansion of the materials tested in this study showed a tendency to decrease with increasing holding temperature of the simulated PWHT. In some cases, the materials after the simulated PWHT cannot satisfy those mechanical requirements.
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Dong, Pingsha, and Jeong K. Hong. "Residual Stress Relief in Post-Weld Heat Treatment." In ASME 2008 Pressure Vessels and Piping Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/pvp2008-61210.
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This paper focuses on analysis of weld residual stress relief process during furnace-based uniform post-weld heat treatment (PWHT). Two classes of pressure vessel steels: 2-1/4CrMo and carbon steel are considered in seam weld configurations. It is found that the dominant mechanism for residual stress relief is the creep relaxation that occurs much earlier during a PWHT cycle than typically expected. This phenomenon is further confirmed by experimental data. After a large number of parametric analyses of various PWHT parameters, a simple form of relationship is proposed for relating residuals stress relief to a set of PWHT parameters for the two classes of steels. These parameters include PWHT ramp-up heating time, PWHT holding time, PWHT holding temperature, and weldment thickness.
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Kojima, Masakazu, Madoka Funai, Takashi Dozaki, Osamu Watanabe, and Akihiro Matsuda. "Effect of Strain Rate and Hold Time in Creep-Fatigue Test." In ASME 2013 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/pvp2013-97876.
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The present paper shows the two experimental results for creep-fatigue interaction effects of perforated plate at elevated temperature. (1) The loading history is assumed to be triangle form in fatigue tests, and that in creep-fatigue loading history, the loading rate from compressive strain to tensile strain is assumed to be constant, which vary from fast rate to slow rate in 5 types of strain rate. The slow strain rate loading includes the creep effects to reduce the life span, which is shown to be predicted if the constant loading assumption is assumed. (2) The holding time effect is also investigated. The tensile strain is held to be constant, and holding time is elongated in the present experiments, which is investigated by the fracture analysis.
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Hu, Guiming, Changyu Zhou, Cheng Chen, and Na Lei. "Metal Dusting Corrosion of Alloy Cr5Mo in H2-CO Gas Mixtures." In ASME 2009 Pressure Vessels and Piping Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/pvp2009-77222.
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Metal dusting is a catastrophic phenomena of high temperature corrosion, which occurs in severe carburizing environments (carbon activity aC>1.0) at temperatures 400–900 °C. It causes not only phase changes but also removal of materials (pitting or thinning) and serious material deterioration. The present study focuses on the fundamental understanding of the corrosion of low alloy steels Cr5Mo in carbon-supersaturated environments (50CO-50H2) at 600 °C over different holding times. Scanning-electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), nano-indentation, and nano-scratch tester are used to investigate the microstructure and its mechanical properties. An interesting continuous thick layer composed of Ha¨gg carbide (Fe5C2) and less cementite (Fe3C) was present on top of the samples, which was ever observed in pure iron but not in alloy steels. This layer grew thicker with increasing holding times and showed very different mechanical properties with the carburized layer which was below the Ha¨gg carbide layer. And the carburized layer could not form a continuous and homogeneous layer of Fe3C even in longer holding times. The cementite only formed at grain boundaries. The results show that also as for low alloy steels at very high carbon activities a second iron carbide, Ha¨gg carbide (Fe5C2), forms on the surface instead of the decomposing process of the metastable carbide, cementite (Fe3C).
Reports on the topic "Holding pressure"
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Phillips, Jake. Understanding the impact of inspection on probation. Sheffield Hallam University, 2021. http://dx.doi.org/10.7190/shu.hkcij.05.2021.
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This research sought to understand the impact of probation inspection on probation policy, practice and practitioners. This important but neglected area of study has significant ramifications because the Her Majesty’s Inspectorate of Probation has considerable power to influence policy through its inspection regime and research activities. The study utilised a mixed methodological approach comprising observations of inspections and interviews with people who work in probation, the Inspectorate and external stakeholders. In total, 77 people were interviewed or took part in focus groups. Probation practitioners, managers and leaders were interviewed in the weeks after an inspection to find out how they experienced the process of inspection. Staff at HMI Probation were interviewed to understand what inspection is for and how it works. External stakeholders representing people from the voluntary sector, politics and other non-departmental bodies were interviewed to find out how they used the work of inspection in their own roles. Finally, leaders within the National Probation Service and Her Majesty’s Prisons and Probation Service were interviewed to see how inspection impacts on policy more broadly. The data were analysed thematically with five key themes being identified. Overall, participants were positive about the way inspection is carried out in the field of probation. The main findings are: 1. Inspection places a burden on practitioners and organisations. Practitioners talked about the anxiety that a looming inspection created and how management teams created additional pressures which were hard to cope with on top of already high workloads. Staff responsible for managing the inspection and with leadership positions talked about the amount of time the process of inspection took up. Importantly, inspection was seen to take people away from their day jobs and meant other priorities were side-lined, even if temporarily. However, the case interviews that practitioners take part in were seen as incredibly valuable exercises which gave staff the opportunity to reflect on their practice and receive positive feedback and validation for their work. 2. Providers said that the findings and conclusions from inspections were often accurate and, to some extent, unsurprising. However, they sometimes find it difficult to implement recommendations due to reports failing to take context into account. Negative reports have a serious impact on staff morale, especially for CRCs and there was concern about the impact of negative findings on a provider’s reputation. 3. External stakeholders value the work of the Inspectorate. The Inspectorate is seen to generate highly valid and meaningful data which stakeholders can use in their own roles. This can include pushing for policy reform or holding government to account from different perspectives. In particular, thematic inspections were seen to be useful here. 4. The regulatory landscape in probation is complex with an array of actors working to hold providers to account. When compared to other forms of regulation such as audit or contract management the Inspectorate was perceived positively due to its methodological approach as well as the way it reflects the values of probation itself. 5. Overall, the inspectorate appears to garner considerable legitimacy from those it inspects. This should, in theory, support the way it can impact on policy and practice. There are some areas for development here though such as more engagement with service users. While recognising that the Inspectorate has made a concerted effort to do this in the last two years participants all felt that more needs to be done to increase that trust between the inspectorate and service users. Overall, the Inspectorate was seen to be independent and 3 impartial although this belief was less prevalent amongst people in CRCs who argued that the Inspectorate has been biased towards supporting its own arguments around reversing the now failed policy of Transforming Rehabilitation. There was some debate amongst participants about how the Inspectorate could, or should, enforce compliance with its recommendations although most people were happy with the primarily relational way of encouraging compliance with sanctions for non-compliance being considered relatively unnecessary. To conclude, the work of the Inspectorate has a significant impact on probation policy, practice and practitioners. The majority of participants were positive about the process of inspection and the Inspectorate more broadly, notwithstanding some of the issues raised in the findings. There are some developments which the Inspectorate could consider to reduce the burden inspection places on providers and practitioners and enhance its impact such as amending the frequency of inspection, improving the feedback given to practitioners and providing more localised feedback, and working to reduce or limit perceptions of bias amongst people in CRCs. The Inspectorate could also do more to capture the impact it has on providers and practitioners – both positive and negative - through existing procedures that are in place such as post-case interview surveys and tracking the implementation of recommendations.