Zeitschriftenartikel: „Holding pressure“

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PALOU, ENRIQUE, AURELIO LÓPEZ-MALO, GUSTAVO V. BARBOSA-CÁNOVAS, JORGE WELTI-CHANES und BARRY G. SWANSON. „Oscillatory High Hydrostatic Pressure Inactivation of Zygosaccharomyces bailii“. Journal of Food Protection 61, Nr. 9 (01.09.1998): 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 und 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, Nr. 9 (01.09.2016): 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 und G. T. Ford. „Effect of lung volume on breath holding“. Journal of Applied Physiology 62, Nr. 5 (01.05.1987): 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 und 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 und 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 und 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, Nr. 4 (01.04.2009): 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 und 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, Nr. 7 (Juli 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 und 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, Nr. 6 (2001): 224–30. http://dx.doi.org/10.11618/adhesion.37.224.

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Zhu, Lai Yu, Chun Peng Chu und Bing Yan Jiang. „Research on Warpage of the Microfluidic Chip in Injection Molding Process“. Advanced Materials Research 926-930 (Mai 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 und 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, Nr. 4 (28.08.2011): 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.

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Wang, Jian, Peng Cheng Xie, Yu Mei Ding und Wei Min Yang. „Study on the End-Point Control of Holding Phase during Injection Molding“. Advanced Materials Research 87-88 (Dezember 2009): 222–27. http://dx.doi.org/10.4028/www.scientific.net/amr.87-88.222.

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While the transfer from filling to packing is particularly crucial during injection molding, the transfers from packing to holding and holding to screw recovery also significantly affect part quality. In this study, the control of the transfer from holding to screw recovery, that is the control of the end-point of the holding phase, was examined. The holding end-point control by time, cavity pressure and cavity temperature were presented. The purpose of this study was to validate the feasibility of the control methods of holding end-point by cavity pressure and cavity temperature. The qualities of injection-molded parts, weight, will serve as measures to probe their process capabilities. Recently found to be a good indicator of product quality, both cavity pressure and temperature profiles are applied here to obtain more precise control. Change of mold temperature was specially considered. After the experimental verification is conducted, the results reveal that the innovative holding end-point control by cavity temperature yields a more uniform product weight with mold temperature. It proved that the holding end-point control by cavity temperature can be used to obtain the optimum holding time and accommodate the product weight to the change of mold temperature, which is the other holding control methods cannot obtain.

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Wang, Jian, Peng Cheng Xie und Wei Min Yang. „End-Point Control of Holding Phase Based on Cavity Pressure for Injection Molding“. Advanced Materials Research 221 (März 2011): 333–37. http://dx.doi.org/10.4028/www.scientific.net/amr.221.333.

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While the switchover from filling to packing is particularly crucial during injection molding, the transfers from holding to screw recovery also significantly affects the quality of molded parts. In this study, the end-point control of the holding phase based on cavity pressure was presented. It was compared with the traditional control method by holding time. The purpose of this study was to validate the feasibility of the end-point control of holding phase by cavity pressure, and to examine its consistency. The weight of the molded parts served as the main measure to probe the process’s capabilities. The results of the verification experiments revealed that the end-point control mode based on cavity pressure could yield better consistency of part weight than the traditional control method by holding time, however, the benefits were not significant. The trigger value of cavity pressure and sensor position should be considered for achieving such high process capabilities.

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AOYAMA, Yasushi, Yujin SHIGETA, Takashi OKAZAKI, Yoshio HAGURA und Kanichi SUZUKI. „Non-thermal Inactivation of Bacillus Spores by Pressure-holding“. Food Science and Technology Research 11, Nr. 3 (2005): 324–27. http://dx.doi.org/10.3136/fstr.11.324.

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Saravanakumar,, N., und R. Marappan,. „Cylindrical Cup Drawing with Hydrodynamic Pressure Assisted Blank Holding“. Journal for Manufacturing Science and Production 7, Nr. 3-4 (Dezember 2006): 151–60. http://dx.doi.org/10.1515/ijmsp.2006.7.3-4.151.

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Iwase, Kazuhiro, Tetsuto Takao, Hirotoshi Watanabe, Yasuhiro Tanaka, Tetsuo Kido, Noritusugu Ogawa, Norio Ono und Hiroshi Yoshitake. „Intra-Abdominal Venous Pressure During Laparoscopic Cholecystectomy“. HPB Surgery 8, Nr. 1 (01.01.1994): 13–17. http://dx.doi.org/10.1155/1994/13689.

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Superior vena cava (SVC) and inferior vena cava (IVC) pressures were measured serially during laparoscopic cholecystectomy in which the intra-abdominal pressure was maintained at 12mmHg. The influences of alteration of position from 15 degrees head-down to 15 degrees head-up and of the operative procedure of holding the gallbladder up to the right subphrenic space on SVC and IVC pressures were mild. IVC pressure was maintained almost equal to the intra-abdominal pressure during prolonged continuous pneumoperitoneum lasting longer than 60min, while SVC pressure did not change significantly during operation. The discrepancy between SVC and IVC pressures underwent no change during continuous pneumoperitoneum.

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Wang, Zi Jian, Ya Xu, Ming Lin Zhou, Yi Lin Wang und Yi Sheng Zhang. „Valuation Method for Effects of Hot Stamping Parameters on Tailored Properties“. Advanced Materials Research 1063 (Dezember 2014): 202–6. http://dx.doi.org/10.4028/www.scientific.net/amr.1063.202.

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The effects of hot stamping parameters including die temperature and holding pressure was evaluated throughout the orthogonal experiment method. Regardless of the effect of the holding pressure, when the die temperature was lower than 400 °C, the lowest hardness emerged at the air gap. The range of transition zone expanded as the die temperature increased. When the die temperature was set at 400 °C, the hardness with 20MPa holding pressure was higher than others, which resulted by considering both the effect of cooling rate and strain.

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Zong, Wei, Yi Heng Cao, Si Qun Jing, Hui Shi und Guang Yuan Zhao. „Optimization for Ultra High Pressure Isomerization of Lycopene“. Advanced Materials Research 781-784 (September 2013): 1430–33. http://dx.doi.org/10.4028/www.scientific.net/amr.781-784.1430.

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To isomerizate of lycopene by ultra high pressure (UHP) method, based on single factor experiments, orthogonal test was used to optimum the isomerization conditions. UHP pressure, UHP holding time, temperature were as factors and ratio of cis-lycopene in total lycopene was as index. The results were as follows: 50°C, UHP pressure 500MPa and holding time 7min. The ratio of cis-lycopene in total lycopene was 45.1%. So UHP combine heating has a isomerization effect on lycopene.

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Yi, Deng Li, und Gui Li Yin. „Effect of Tempering Holding Time on Performance of Wear-Resistant Steel of High Pressure Blower Impeller“. Advanced Materials Research 299-300 (Juli 2011): 1107–10. http://dx.doi.org/10.4028/www.scientific.net/amr.299-300.1107.

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As ventilation and dust removal equipment, high pressure blower is widely used in industry, but the heavy wear of impeller which is the core frame member of the equipment still restrict the fully increasing in the performance of the high pressure blower. So it has important significance to research and develop wear-resisting impeller of high pressure blower. The article focused on studying the microstructure and hardness of the experimental steel used in the wear-resisting impeller of high pressure blower, subjected to be processed in different tempering holding time; as well as analyzing the mechanism of the influence of tempering holding time on the experimental steel. The results show that, with the increasing in holding time, lath-shaped tempered martensite becomes obscure in experimental steel used in the Q-tempered wear-resisting impeller of high pressure blower, as well as the account of acicular martensite and bainite also increases, resulting in the gradual decreasing in hardness. Furthermore, the hardness of alloy steel decreases sharply when the holding time is more than 60 min. Thereby, the best holding time of alloy steel is considered to be 40 to 60 min.

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Hu, Ran, Min Zhang, Benu Adhikari und Yaping Liu. „Effect of homogenization and ultrasonication on the physical properties of insoluble wheat bran fibres“. International Agrophysics 29, Nr. 4 (01.10.2015): 423–32. http://dx.doi.org/10.1515/intag-2015-0048.

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AbstractWheat bran is rich in dietary fibre and its annual output is abundant, but underutilized. Insoluble dietary fibre often influences food quality negatively; therefore, how to improve the physical and chemical properties of insoluble dietary fibre of wheat bran for post processing is a challenge. Insoluble dietary fibre was obtained from wheat bran and micronized using high-pressure homogenization, high-intensity sonication, and a combination of these two methods. The high-pressure homogenization and high-pressure homogenization+high-intensity sonication treatments significantly (p<0.05) improved the solubility, swelling, water-holding, oil-holding, and cation exchange capacities. The improvement of the above properties by high-intensity sonication alone was marginal. In most cases, the high-pressure homogenization process was as good as the high-pressure homogenization+high-intensity sonication process in improving the above-mentioned properties; hence, the contribution of high-`intensity sonication in the high-pressure homogenization+high-intensity sonication process was minimal. The best results show that the minimum particle size of wheat bran can reach 9 μm, and the solubility, swelling, water-holding, oil-holding, cation exchange capacities change significantly.

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Wang, Chenxiao, Hao Yin, Yanyun Zhao, Yan Zheng, Xuebing Xu und Jin Yue. „Optimization of High Hydrostatic Pressure Treatments on Soybean Protein Isolate to Improve Its Functionality and Evaluation of Its Application in Yogurt“. Foods 10, Nr. 3 (20.03.2021): 667. http://dx.doi.org/10.3390/foods10030667.

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This work aimed to improve the functional properties of soybean protein isolate (SPI) by high hydrostatic pressure (HHP) and develop SPI incorporated yogurt. Response surface methodology (RSM) was used to optimize the HHP treatment parameters, including pressure, holding time, and the ratio of SPI/water. Water holding capacity, emulsifying activity index, solubility, and hardness of SPI gels were evaluated as response variables. The optimized HPP treatment conditions were 281 MPa of pressure, 18.92 min of holding time, and 1:8.33 of SPI/water ratio. Water and oil holding capacity, emulsifying activity, and stability of SPI at different pH were improved. Additionally, relative lipoxygenase (LOX) activity of HHP treated SPI (HHP-SPI) was decreased 67.55 ± 5.73%, but sulphydryl group content of HHP-SPI was increased 12.77%, respectively. When incorporating 8% of SPI and HHP-SPI into yogurt, the water holding capacity and rheological properties of yogurt were improved in comparison with yogurt made of milk powders. Moreover, HHP-SPI incorporated yogurt appeared better color and flavor.

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Wu, Paula, Peter A. Bandettini, Ronald M. Harper und Daniel A. Handwerker. „Effects of Thoracic Pressure Changes on MRI Signals in the Brain“. Journal of Cerebral Blood Flow & Metabolism 35, Nr. 6 (25.02.2015): 1024–32. http://dx.doi.org/10.1038/jcbfm.2015.20.

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Cerebrovascular stressors, such as breath holding or CO2 inhalation, cause global magnetic resonance imaging (MRI) signal changes. In this study, we show that intrathoracic pressure changes cause rapid MRI signal alterations that have similar spatial patterns to the changes associated with breath holding or CO2 inhalation. Nine subjects performed the Valsalva maneuver during functional MRI data collection. Expiratory pressures ranged from 10 to 40 mm Hg. Breath holds ending on either inhalation or exhalation were also collected. The maximal and minimal functional MRI (fMRI) signal scaled with thoracic pressure load, and the overall amplitude of responses to the Valsalva varied, depending on brain tissue. Additionally, a Valsalva effort as short as 5 seconds yielded signal changes similar in spatial distribution and magnitude to a 20-second breath hold, suggesting potential applications of the Valsalva maneuver for calibrated fMRI experiments.

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Yan, QingSong, Huan Yu, ZhiFeng Xu, BoWen Xiong und ChangChun Cai. „Effect of holding pressure on the microstructure of vacuum counter-pressure casting aluminum alloy“. Journal of Alloys and Compounds 501, Nr. 2 (Juli 2010): 352–57. http://dx.doi.org/10.1016/j.jallcom.2010.04.103.

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Wang, Yilei, und Chunlan Jiang. „Influence of Molding Parameters on Quasi-Static Mechanical Properties of Al-Rich Al/PTFE/TiH2 Active Materials“. Materials 14, Nr. 11 (22.05.2021): 2750. http://dx.doi.org/10.3390/ma14112750.

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Preforming pressure and the pressure holding time are important parameters of the molding process, which directly affect the mechanical properties of materials. In order to obtain the best molding parameters of Al-rich Al/PTFE/TiH2 composites, based on the quasi-static compression test, the influence of molding parameters on the mechanical properties of Al-rich Al/PTFE/TiH2 composites was analyzed, and the microstructure characteristics of Al-rich Al/PTFE/TiH2 specimens were analyzed by SEM. An X-ray diffractometer was used to analyze the phase of the residue after quasi-static compression experiment. The results show that: (1) With the increase in molding parameters (preforming pressure and the pressure holding time), the compressive strength, failure strain and toughness of Al-rich Al/PTFE/TiH2 specimens first increase and then decrease. The best molding process parameters of Al-rich Al/PTFE/TiH2 materials are preforming pressure 240 MPa and the pressure holding time 100 s. (2) For unsintering specimens, when the preforming pressure is less than 150 MPa, the porosity of the specimen increases slowly at first and then decreases. When the preforming pressure is greater than 150 MPa, the porosity of the specimen increases first and then decreases. When the pressure holding time is no more than 100 s, the porosity of the specimen decreases gradually. When the pressure holding time is more than 100 s, the porosity of the specimen increases first and then decreases. For sintered specimens, when the preforming pressure is less than 100 MPa, the porosity of the specimen decreases gradually. When the preforming pressure is greater than 100 MPa, the porosity of the specimen first increases and then decreases. With the increase in the pressure holding time, the porosity first increases and then decreases. For each preforming pressure specimen, compared with that before sintering, the porosity after sintering either decreases or increases. For each the pressure holding time specimen, the porosity increases after sintering compared with that before sintering. The microstructure of PTFE crystal inside the specimen is mainly planar PTFE crystal. The size and number of planar PTFE crystals are significantly affected by the molding parameters, which further affects the mechanical properties of Al-rich Al/PTFE/TiH2 specimens. When the preforming pressure is less than 100 MPa, the planar PTFE crystals are small and few, which results in the worst mechanical properties of the specimens. When the preforming pressure is more than 100 MPa and does not contain 240 Mpa, the planar PTFE crystals are small and there are more of them, which results in better mechanical properties of the specimens. When the preforming pressure is 240 MPa, the planar PTFE crystals are large and numerous, which results in the best mechanical properties of the specimen. When the pressure holding time is 100 s, the planar PTFE crystals are large and there are more of them, which results in the best mechanical properties of the specimen. (3) The reactivity of Al-rich Al/PTFE/TiH2 specimens with TiH2 the content of 10% under quasi-static compression is not significantly affected by the molding parameters.

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Sato, Hideki, Kenichi Manabe, Tsuyoshi Furushima, Dong Bin Wei, Zheng Yi Jiang und Sergei Alexandrov. „On the Scale Dependence of Micro Hydromechanical Deep Drawing“. Key Engineering Materials 725 (Dezember 2016): 689–94. http://dx.doi.org/10.4028/www.scientific.net/kem.725.689.

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Tooling feature size to minimum thickness becomes small in micro scale products and its ratio affects the deformation behavior in micro sheet forming significantly. In this study, the effect of this relative tooling feature size on drawing characteristics and effects to improve the drawability, such as friction holding effect, hydrodynamic lubrication effect and compression effect by blank edge radial pressure, in micro hydromechanical deep drawing (MHDD) are investigated using plasticity theory and numerical simulation. The results show that the micro drawing characteristics in MHDD can be improved by applying counter pressure. However, the required fluid pressures for friction holding and hydrodynamic lubrication effects increase as the relative punch diameter and/or die shoulder radius to thickness decrease, although the compression effect by radial pressure on the blank edge is independent of the relative tooling feature size.

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CROSS, TROY J., TONI BRESKOVIC, SURENDRAN SABAPATHY, PETRA ZUBIN MASLOV, BRUCE D. JOHNSON und ZELJKO DUJIC. „Respiratory Muscle Pressure Development during Breath Holding in Apnea Divers“. Medicine & Science in Sports & Exercise 45, Nr. 1 (Januar 2013): 93–101. http://dx.doi.org/10.1249/mss.0b013e3182690e6a.

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Fiz, J. A., A. Carreres, A. Rosell, J. M. Montserrat, J. Ruiz und J. M. Morera. „Measurement of maximal expiratory pressure: effect of holding the lips.“ Thorax 47, Nr. 11 (01.11.1992): 961–63. http://dx.doi.org/10.1136/thx.47.11.961.

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Thiruvarudchelvan, S., und W. G. Lewis. „Deep Drawing With Blank Holder Force Approximately Proportional to the Punch Force“. Journal of Engineering for Industry 112, Nr. 3 (01.08.1990): 278–85. http://dx.doi.org/10.1115/1.2899587.

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A new method of applying blank holding force approximately proportional to the punch force in cup drawing is presented. An annular urethane pad compressed between two parts of a punch expands and applies pressure against the tubular part of a blank holder. As the punch moves to draw the blank, friction between the urethane pad and the blank holder applies automatically a blank holding force approximately proportional to the punch force. Experimental investigations were carried out with aluminum blanks to determine the optimum conditions to obtain wrinkle-free cups. Variations of the punch force and the blank holding force with punch stroke for aluminum blanks under different degrees of wrinkling are presented. Strains on the cup wall measured with this method are presented and compared with those obtained under constant blank holding force conditions. Theoretical critical blank holding pressure variation with punch stroke is compared with the pressure variation that obtains with the present method. Using the deep drawing theory an expression to predict the punch force with this method is also presented.

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Amran, Mohd, Siti Salmah, Mohd Zaki, Raja Izamshah, Mohd Hadzley, Sivarao, Mohd Shahir Kasim und Mohd Amri. „The Effect of Pressure on Warpage of Dumbbell Plastic Part in Injection Moulding Machine“. Advanced Materials Research 903 (Februar 2014): 61–66. http://dx.doi.org/10.4028/www.scientific.net/amr.903.61.

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The optimization of processing parameters on warpage of polypropylene (PP) in the application of injection moulding machine was studied. The appropriate parameters were adjusted to reduce the warpage defect on the tensile test specimen of dumbbell. The type of injection moulding machine used in this research is Arburg 420C 800-250C. Four parameters that have been investigated; injection pressure, clamping pressure, back pressure and holding pressure. A concept of design of experiment (DOE) has been applied using Taguchi method to determine the suitable parameters. To measure the warpage of the dumbbell, digital height gauge was used to measure the flatness of the part surface. According the analysis of variance (ANOVA), the most significant factor that effect the warpage was holding pressure by 57.82%, followed with back pressure by 25.75%, clamping pressure by 16.27% and injection pressure by 0.16%. It is found that the optimum parameters setting that have been obtained were injection pressure at 950 bar, clamping pressure at 600 kN, holding pressure at 700 bar and back pressure at 75 bar. The depreciation value of warpage minimum index in this experiment was decreased by 4.6% after confirmation run.

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Sudarisman und Ian J. Davies. „Influence of Compressive Pressure, Vacuum Pressure, and Holding Temperature Applied during Autoclave Curing on the Microstructure of Unidirectional CFRP Composites“. Advanced Materials Research 41-42 (April 2008): 323–28. http://dx.doi.org/10.4028/www.scientific.net/amr.41-42.323.

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The microstructure (i.e., fibre volume fraction, void content, and fibre misalignment) of unidirectional carbon fibre-reinforced polymer (CFRP) composites was optimised by controlling several parameters during manufacture, namely: (i) compressive pressure (0.25~1.25 MPa, in steps of 0.25 MPa), (ii) vacuum pressure (−0.15, −0.20, −0.30, −0.45, and −0.65 MPa), and (iii) holding temperature (100~140 oC, in steps of 10 oC), applied during autoclave curing with the holding time being 30 minutes for all specimens. Optical micrographs captured from cross-sectional, through-the thickness areas, and in-plane areas of the resulting composites were evaluated and analysed in order to describe their microstructural characteristics.

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Tao, Xue, Yao Zhan, Qiu Yan Zhou, Feng Qin Feng und Yong Yu. „Optimization of Ultra-High Pressure Extraction Process of Polysaccharides from Dendrobium Candidum by Response Surface Method“. Advanced Materials Research 550-553 (Juli 2012): 1796–800. http://dx.doi.org/10.4028/www.scientific.net/amr.550-553.1796.

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Ultra-high pressure extraction technique was used to extract polysaccharides from Dendrobium candidum. Extraction pressure, pressure holding time and liquid-solid ratio were found to have a significant influence on the polysaccharides extraction and were optimized by the response surface method (RSM). The obtained optimum conditions were: extraction pressure 445.28MPa, pressure holding time 6.7 minutes and liquid-solid ratio 237.91ml/g. The maximum polysaccharide yield could reach 596.75mg/g under these conditions. The ultra-high pressure extraction process was a suitable method for its higher yield and shorter extraction time compared to the water-heating extraction.

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Chiu, Cheng Ping, und Min Chin Hsieh. „The Correlation Between the Residual Stresses of ABS Terpolymers and Injection Molding Conditions“. Journal of Engineering Materials and Technology 109, Nr. 2 (01.04.1987): 171–75. http://dx.doi.org/10.1115/1.3225958.

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Residual stresses (R.S.) in a microcomputer-controlled injection molded ABS terpolymers have been determined. The layer-removal method and the microscopic measurement techniques were used to evaluate the stresses in these molded articles. The relationship between the R.S. and the processing parameters such as injection pressure, holding pressure, holding time, injection rate, and mold temperature was studied. Experimental results indicated that, at the higher injection rates (>10g/s), the R.S. are compressive in the surface layer and tensile in the interior; however, at the lower injection rates (<10g/s), the residual stresses are tensile in the surface layer and compressive in the interior. The results also indicated that the higher the injection rate, the lower the residual stresses; the compressive residual stresses increased in proportion to the increase of holding pressure; the residual stresses could be decreased by keeping a higher mold temperature; the longer the holding time, the higher the compressive R.S. and the lower the tensile R.S.

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He, Yong, Ting Zhang, Jian Zhong Fu und Zi Chen Chen. „Experimental Study on the Fabrication of the Light Guide Plate with Hot Embossing Method“. Applied Mechanics and Materials 37-38 (November 2010): 448–52. http://dx.doi.org/10.4028/www.scientific.net/amm.37-38.448.

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To improve the quality of the light guide plate (LGP) made by injection molding, a fabrication method based on hot embossing was proposed. The silicon mold of the LGP with micro pyramid array was fabricated by wet chemical etching. The experiments of embossing the LGP were performed with a self-designed hot embossing machine. Orthogonal method was used to analyze the imprint pressure, the holding time, the imprint temperature and the width of pyramid with respect to the accuracy of replication (AOR). The experimental results show that the imprint temperature has the greatest effect on the AOR, followed by the imprint pressure and the holding time, while the width of micro pyramid has the minimal effect on the AOR. The increase of imprint temperature can obviously improve the pattern filling quality in the lower imprint pressure (0.7MPa). At last the optimal process parameters were obtained with the imprint pressure of 0.9MPa, the holding time of 5min and the imprint temperature of 130°C.

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Kulkarni, Sumedh, Syed Nadeem Akhtar und Janakarajan Ramkumar. „Experimental Investigation of Formability Enhancement Using Hydraulic Counter Pressure Assisted Warm Deep Drawing“. Advanced Materials Research 299-300 (Juli 2011): 364–67. http://dx.doi.org/10.4028/www.scientific.net/amr.299-300.364.

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Deep drawing processes are widely utilized in mechanical industries for producing several typologies of products ranging from computer industry to automotive components, from house products to furniture products. The goal of this study is to verify experimentally the warm deep drawing process assisted with hydraulic counter pressure as a suitable alternative to conventional deep drawing as a means for producing defect-free sheet metal parts. Using specific process parameters like blank holding pressure, blank diameter and temperature, wrinkle-free parts with deeper draws could be produced. An enhancement in LDR from 2.06 in conventional deep drawing to 2.16 in warm deep drawing with a lower blank holding pressure is achieved. The lower blank holding pressure leads to lesser thickness variation in the product this reducing the occurrence of fracture at the punch radius. The hydraulic counter pressure helps in reduction of wrinkles and enhancement of formability. The improvement in the LDR was observed around 200°C for warm deep drawing. This process reduces the forming restrictions of many materials, can produce complicated shapes and reduces the costs of material and die.

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Ferrigno, M., D. D. Hickey, M. H. Liner und C. E. Lundgren. „Simulated breath-hold diving to 20 meters: cardiac performance in humans“. Journal of Applied Physiology 62, Nr. 6 (01.06.1987): 2160–67. http://dx.doi.org/10.1152/jappl.1987.62.6.2160.

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Cardiac performance was assessed in six subjects breath-hold diving to 20 m in a hyperbaric chamber, while nonsubmersed or submersed in a thermoneutral environment. Cardiac index and systolic time intervals were obtained with impedance cardiography and intrathoracic pressure with an esophageal balloon. Breath holding at large lung volume (80% vital capacity) decreased cardiac index, probably by increasing intrathoracic pressure and thereby impeding venous return. During diving, cardiac index increased (compared with breath holding at the surface) by 35.1% in the nonsubmersed and by 29.5% in the submersed condition. This increase was attributed to a fall in intrathoracic pressure. Combination of the opposite effects of breath holding and diving to 20 m left cardiac performance unchanged during the dives (relative to the surface control). A larger intrathoracic blood redistribution probably explains a smaller reduction in intrathoracic pressure observed during submersed compared with nonsubmersed diving. Submersed breath-hold diving may entail a smaller risk of thoracic squeeze (lesser intrathoracic pressure drop) but a greater risk of overloading the central circulation (larger intrathoracic blood pooling) than simulated nonsubmersed diving.

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Albalate, Daniel, und Germà Bel. „Tourism and urban public transport: Holding demand pressure under supply constraints“. Tourism Management 31, Nr. 3 (Juni 2010): 425–33. http://dx.doi.org/10.1016/j.tourman.2009.04.011.

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36

Petera, Pavel. „THE INFLUENCE OF HOLDING PRESSURE ON POWDER DISTRIBUTION IN PIM TECHNOLOGY“. MM Science Journal 2012, Nr. 02 (27.06.2012): 327–29. http://dx.doi.org/10.17973/mmsj.2012_07_201208.

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Xie, Jiuming, Shiyu Wang, Zhongbao Cui und Jin Wu. „Process Optimization for Compression Molding of Carbon Fiber–Reinforced Thermosetting Polymer“. Materials 12, Nr. 15 (30.07.2019): 2430. http://dx.doi.org/10.3390/ma12152430.

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To enhance the quality and mechanical performance of a carbon fiber–reinforced polymer (CFRP) workpiece, this paper prepares a polyacrylonitrile (PAN)-based carbon fiber–reinforced thermosetting polymer (CFRTP) laminated board through compression molding, and carries out orthogonal tests and single-factor tests to disclose the effects of different process parameters (i.e., compression temperature, compression pressure, pressure-holding time, and cooling rate) on the mechanical performance of the CFRTP workpieces. Moreover, the process parameters of compression molding were optimized based on the test results. The research results show that: The process parameters of compression molding can be ranked as compression temperature, pressure-holding time, compression pressure, cooling rate, and mold-opening temperature, in descending order of the impact on the mechanical property of the CFRTP; the optimal process parameters for compression molding include a compression temperature of 150 °C, a pressure-holding time of 20 min, a compression pressure of 50 T, a cooling rate of 3.5 °C/min, and a mold-opening temperature of 80 °C. Under this parameter combination, the tensile strength, bending strength, and the interlaminar shear strength (ILSS) of the samples were, respectively, 785.28, 680.36, and 66.15 MPa.

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Bekhovykh, Yuriy, Larisa Bekhovykh, Aleksey Lyoevin und Evgeniy Sizov. „Changes in maximum water holding capacity of chernozem soil caused by soil compaction“. E3S Web of Conferences 262 (2021): 03003. http://dx.doi.org/10.1051/e3sconf/202126203003.

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The goal of the studies presented in the work is to estimate the changes in the maximum water holding capacity of the soil caused by soil compaction. The object of the research is a loam type of chernozem soil. The research shows that the maximum water holding capacity is a function of the soil density change and indirectly depends on the action of soil compaction factors, including external pressure level, the number of impacts on soil cover, as well as on soil moisture. Soil moisture is indicated as the most important factor in changing the maximum water holding capacity caused by soil compaction. The decrease in the maximum water holding capacity caused by soil compaction is more obvious with an increase in soil moisture, both in the research of the number of impacts and external pressure influence on this indicator. The results of the work show that the change in the maximum water holding capacity caused by a compacting action significantly depends on the initial value of the soil addition density.

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Wang, Rui Cai, Jian Yong Shi, Sheng Chen und Hua Jie Chen. „Experimental Study on the Time Effect of the Jacked Pile“. Applied Mechanics and Materials 353-356 (August 2013): 125–29. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.125.

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Based on the strain-holding test by using GDS stress path triaxial apparatus, the changes of pore water pressure and stress of soil around the pile were simulated during and after pile jacking. Test results show as follows: excess pore water pressure and effective stress increment increase with strain and initial stress rising at the stage of strain applied. And at the stage of strain holding, effective stress increment increases with rising of strain and initial stress. For the total effective stress increment, the proportion of effective stress increment is large at the stage of strain applied. And at the stage of strain holding, the proportion of effective stress increment is small.

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S., Anuja B., Elsa Sanatombi Devi, Leena Sequira, Lavanya Rao und Vijaya Pai H. „EFFECTIVENESS OF INTRA OPERATIVE HAND HOLDING ON ANXIETY AND PHYSIOLOGICAL PARAMETERS AMONG PATIENTS UNDERGOING CATARACT SURGERY“. Journal of Health and Allied Sciences NU 04, Nr. 02 (Juni 2014): 027–33. http://dx.doi.org/10.1055/s-0040-1703760.

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Abstract: Introduction: Patients who are undergoing cataract surgery under local anaesthesia may be more stressed than those having general anaesthesia as they are awake during the surgical procedure. Therefore, psychological comfort in the preoperative phase and compliance during operation are very important for postoperative prognosis. This study explored the pre operative anxiety level of patients undergoing cataract surgery and the effectiveness of intra operative hand holding on anxiety and its related physiological parameters. Methods: A quasi experimental pre-test post-test control group design was used to collect data from a purposive sample of 54 patients who were underwent cataract surgery at Kasturba Hospital, Manipal. Results: Most of the patients in the experimental group perceived intra operative hand holding as a measure to reduce their anxiety even though there was no significant statistical difference in the immediate post operative anxiety score between the groups. It was also found that hand holding was effective in reducing blood pressure and heart rate except the respiratory rate of patients undergoing cataract surgery. Conclusion: The following conclusions were drawn on the basis of the findings of the present study that is, Intra operative hand holding was effective in reducing the physiological parameters such as heart rate, systolic blood pressure and diastolic blood pressure. Also most of the patients perceived intra operative hand holding as beneficial in relieving anxiety.

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Dai, Guangming, Lihua Zhan, Chenglong Guan und Minghui Huang. „Optimization of molding process parameters for CF/PEEK composites based on Taguchi method“. Composites and Advanced Materials 30 (01.01.2021): 263498332110018. http://dx.doi.org/10.1177/26349833211001882.

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In this article, nine groups of laminates were prepared according to the Taguchi L9(33) test array to study the influence of three process parameters, including molding pressure, molding temperature, and holding time on the performance of unidirectional carbon fiber/polyetheretherketone (CF/PEEK) laminates. A differential scanning calorimetry test was employed to select a reasonable process parameters range. The transverse tensile strength of the laminates was measured, and the fiber–matrix interfacial bonding behavior of the tested samples was analyzed by scanning electron microscopy. The results showed that the significance of factors to transverse tensile strength were molding temperature, holding time, and molding pressure in sequence. The optimal molding process parameters for CF/PEEK composite laminate were molding temperature of 400°C, molding pressure of 3 MPa, and holding time of 30 min. The optimization results were meaningful for the extension and application of thermoplastic composites.

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Roth, Benedikt, und Dietmar Drummer. „Pressure Equilibrium Time of a Cyclic-Olefin Copolymer“. Polymers 13, Nr. 14 (14.07.2021): 2309. http://dx.doi.org/10.3390/polym13142309.

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Integrative simulation techniques for predicting component properties, based on the conditions during processing, are becoming increasingly important. The calculation of orientations in injection molding, which, in addition to mechanical and optical properties, also affect the thermal shrinkage behavior, are modeled on the basis of measurements that cannot take into account the pressure driven flow processes, which cause the orientations during the holding pressure phase. Previous investigations with a high-pressure capillary rheometer (HPC) and closed counter pressure chamber (CPC) showed the significant effect of a dynamically applied pressure on the flow behavior, depending on the temperature and the underlying compression rate. At a constant compression rate, an effective pressure difference between the measuring chamber and the CPC was observed, which resulted in a stop of flow through the capillary referred to as dynamic compression induced solidification. In order to extend the material understanding to the moment after dynamic solidification, an equilibrium time, which is needed until the pressure signals equalize, was evaluated and investigated in terms of a pressure, temperature and a possible compression rate dependency in this study. The findings show an exponential increase of the determined equilibrium time as a function of the holding pressure level and a decrease of the equilibrium time with increasing temperature. In case of supercritical compression in the area of a dynamic solidification, a compression rate dependency of the determined equilibrium times is also found. The measurement results show a temperature-invariant behavior, which allows the derivation of a master curve, according to the superposition principle, to calculate the pressure equilibrium time as a function of the holding pressure and the temperature.

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Zhang, Hua Yong, Cong Sheng Guan, Tian Duo Li und Xiao Deng Yang. „Technology of Polyphenylene Sulfide (PPS) Resin/Graphite Conductive Composite for Bipolar Plate“. Key Engineering Materials 519 (Juli 2012): 49–52. http://dx.doi.org/10.4028/www.scientific.net/kem.519.49.

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A kind of conductive composite material for the bipolar plate of proton-exchange membrane fuel cells (PEMFC) was fabricated by the hot-pressure molding with graphite powders and polyphenylene sulfide (PPS) resin powders. The influencing factors including PPS resin content, molding pressure and molding temperature, and temperature holding time on the conductivity, flexural strength and density of the composite were investigated. It was found that the perfect conditions for the fabrication of bipolar plate were that the PPS resin content was 25%wt, the forming pressure was 20 MPa, the mold temperature was 320°C and the holding time was 25 min.

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Guo, Zhi Hong, Hua Hou, Yu Hong Zhao und Shu Wei Qu. „Experimental Study of Squeeze Casting of AZ31 Magnesium Alloy“. Advanced Materials Research 532-533 (Juni 2012): 16–19. http://dx.doi.org/10.4028/www.scientific.net/amr.532-533.16.

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A new high-strength magnesium alloy with better properties than that of AZ31 was developed. The effect of applied pressure during squeeze casting on microstructures and properties of the alloy was studied by means of techniques such as standard mechanical tester, Brinell Hardness Tester (BHT), and Metallographic Microscope (MM). The parameters studied include squeeze casting pressure, melt temperature and pressure holding time by using orthogonal experimental method. It was found that a squeeze casting pressure of 110 MPa and a melt and pressure holding time of 700 °C and 15s respectively gave a good combination of mechanical properties in AZ31 Mg alloy. This was primarily due to effective die ﬁlling, microstructural reﬁnement and good heat transfer between the molten metal and the mould.

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Suraj R. Marathe und Dr. Carmo E. Quadros. „Analysis and Optimisation of High Pressure Die Casting Parameters to Achieve Six Sigma Quality Product Using Numerical Simulation Approach“. International Journal of Engineering and Management Research 11, Nr. 1 (12.02.2021): 97–109. http://dx.doi.org/10.31033/ijemr.11.1.15.

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A numerical simulation approach is proposed to predict the optimal parameter setting during high pressure die casting. The contribution from the optimal parameters, the temperature, showed more influence on the casting quality than the other parameters. This study’s outcome was beneficial for finding the solution for casting defects that occurs due to incorrect setting of process parameters in die casting. Thus, a combination of numerical optimisation techniques and casting simulation serves as a tool to improve the casting product quality in die casting industries. This paper aims to analyse and optimise critical parameters like injection pressure, molten metal temperature, holding time, and plunger velocity, contributing to the defects. In this research paper, an effort has been made to give optimal pressure, temperature, holding time, and plunger velocity parameters using ProCAST simulation software that uses finite element analysis technology. Numerical analysis for optimising the parameters by varying the temperature of molten metal, injection pressure, holding time, and plunger velocity, concerning solidification time at hot spots, is an essential parameter for studying the defect analysis in the simulated model.

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Bulejko, Pavel, Ondřej Krištof und Miroslav Dohnal. „An Assessment on Average Pressure Drop and Dust-Holding Capacity of Hollow-Fiber Membranes in Air Filtration“. Membranes 11, Nr. 7 (24.06.2021): 467. http://dx.doi.org/10.3390/membranes11070467.

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In this work, we tried to analyze dust loading behavior of polypropylene hollow fiber membranes using average pressure drop models. Hollow fiber membranes varying in fiber diameter were loaded with a standardized test dust to simulate particle-polluted air. We measured pressure drop development of the membranes at different flowrates and dust concentrations, and, after each experiment, the dust deposited on the membrane fibers was weighed to obtain dust holding capacity (DHC). The obtained experimental data was analyzed using various average pressure drop models and compared with average pressure drop obtained from pressure drop/dust load dependence using a curve fit. Exponential and polynomial fitting was used and compared. Pressure drop in relation to the dust load followed different trends depending on the experimental conditions and inner fiber diameter. At higher flowrate, the dependence was polynomial no matter what the fiber diameter. However, with higher fiber diameter at lower permeate velocities, the dependence was close to exponential curve and followed similar trends as observed in planar filter media. Dust-holding capacity of the membranes depended on the experimental conditions and was up to 21.4 g. However, higher dust holding capacity was impossible to reach no matter the experiment duration due to self-cleaning ability of the tested membranes.

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Song, Ru Yin, Hong Wu Yang und Jun De Yang. „Research on the Effect of Holding Time on Diamond Drill Bit Performance“. Advanced Materials Research 634-638 (Januar 2013): 2411–18. http://dx.doi.org/10.4028/www.scientific.net/amr.634-638.2411.

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The sintering parameters of hot-pressing diamond drill bit mainly contains the sintering temperature, holding time, sintering pressure and the pressurized method. The length of holding time is directly related to the performance of diamond drill bit. This article mainly discusses the effect of holding time on the performance of diamond drill bit. First, a general formula of diamond drill bit is chosen. A group of samples in this parameter were loaded and sintered. Holding time is set as variable, while other parameters remain the same. The optimal holding time for this formula is obtained through the mechanical properties tests on the samples’ bending, tension, compression, and hardness, and fracture analysis using scanning electron microscopy (SEM).

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Liu, Chang Hui, Sun Jin, Xin Min Lai, Dong Hong Wang und Yu Lian Wang. „Experimental Study of Injection Conditions for a Thin-Walled Wax Pattern Using Response Surface Methodology“. Applied Mechanics and Materials 607 (Juli 2014): 185–92. http://dx.doi.org/10.4028/www.scientific.net/amm.607.185.

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In this paper, the relationship between the shrinkage of the thin-walled wax part in the investment casting process (ICP) and the process parameters including mold temperature, melt temperature, packing pressure and holding time are investigated through a series of experiments. The relationship is successfully described by a mathematical regression model which is based on the response surface methodology (RSM). The rationality and adequacy of the mathematical model are checked via analysis of variation (ANOVA) and a sensitivity analysis for process parameters on the dimensional shrinkage variation are conducted which shows that the contribution percentages of mold temperature, melt temperature, packing pressure and holding time are 23.77%, 43.67%, 11.85% and 16.99%, respectively. Additionally, the optimal setting of the process parameters is also obtained by calculating the desirability function. The optimal combination of the mold temperature, melt temperature, packing pressure, and holding time is 74°C, 30°C 25bar, and 5 sec, respectively.

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Seprianto, Dicky, Firdaus Firdaus und Fatahul Arifin. „Effect of Holding Time, Grain Size and Compacting Pressure Parameters against Compressive Strength of Aluminum - 5%Fly Ash“. Advanced Materials Research 576 (Oktober 2012): 146–49. http://dx.doi.org/10.4028/www.scientific.net/amr.576.146.

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This research is aimed to analysis the effect of holding time, grain size and compacting pressure parameter against compressive strength of Aluminum-5% fly ash using powder metallurgy method. The irregular form and homogeneous particles of aluminum powder used in this research is produced by Merck German, while fly ash is taken from residual combustion coal in forging process in mechanical engineering workshop of Politeknik Negeri Sriwijaya (Polsri) which is mashed up to grains size 140 and 270 mesh, pressed with holding time 60 and 120 seconds, with compacting pressure 139 N/mm2and 275 N/mm2by cold iso-static pressing. The green body resulted from these processes then sintered up to 550°C. Taguchi Method is used to determine factors which affect optimum condition of compressive strength of Aluminum-5% fly ash. The research result using ANOVA show that the holding time, grains size, , and compacting pressure parameters has significantly affect the compressive strength of Aluminum-5% fly ash.

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Nor, Nor Hafiez Mohamad, Norhamidi Muhamad, Sufizar Ahmad, Mohd Halim Irwan Ibrahim, Mohd Ruzi Harun und Khairur Rijal Jamaludin. „Parameter Optimization of Injection Molding Ti-6Al-4V Powder and Palm Stearin Binder System for Highest Green Density Using Taguchi Method“. Key Engineering Materials 443 (Juni 2010): 69–74. http://dx.doi.org/10.4028/www.scientific.net/kem.443.69.

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In this paper, the titanium alloy powder of Ti-6Al-4V is mixed with binder 60wt% of palm stearin and 40wt% of polyethylene for metal injection molding (MIM) process. Injection molding parameters has been optimized using Taguchi method of L27 (313) orthogonal array. Highest green density has been identified as the green part quality characteristic or as an output for this study. Parameters optimized are the injection pressure, injection temperature, powder loading, mold temperature, holding pressure and injection speed. Besides those, interaction of the injection pressure, injection temperature and powder loading were studied. The analysis of variance (ANOVA) is employed to determine the significant levels (α) and contributions of the variables to the green density. Results show that the injection pressure has highest significant percentage followed by injection temperature, powder loading and holding pressure.

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