Articoli di riviste: "Low-pressure injection"

1

Arès, Francis, Dorian Delbergue e Vincent Demers. "Injection Flow Rate Threshold Preventing Atypical In-Cavity Pressure during Low-Pressure Powder Injection Molding". Powders 2, n. 4 (7 novembre 2023): 709–26. http://dx.doi.org/10.3390/powders2040044.

Testo completo

Abstract (sommario):

Controlling injection parameters is paramount when it comes to producing high-quality green parts using powder injection molding. This work combines experimental and numerical approaches to study the impact of injection parameters on mold in-cavity pressure and on the overall quality of green parts produced by low-pressure powder injection molding. The properties of two low-viscosity feedstocks (formulated from a water-atomized stainless-steel powder and wax-based binder system) were measured and implemented in an Autodesk Moldflow numerical model to quantify the molding pressures, which were finally validated using experimental real-scale injections. The results confirmed that an increase in mold temperature, an increase in feedstock temperature, and a decrease in solid loading decrease the mold in-cavity pressure, which was correlated with the feedstock viscosity. As a key result, real-scale injections confirmed that a minimum flow rate was required to avoid atypical high in-cavity pressure leading to several visual defects such as weld lines, flow marks, cracks, sinks, and incomplete filling. Due to differences in its thermal transfer properties, this flow rate threshold value decreases as the feedstock solid loading increases. For injection speeds higher than this value, the injection pressure measured experimentally was linearly correlated with the injection flow rate.

Gli stili APA, Harvard, Vancouver, ISO e altri

2

Hu, Zhen, Shuang Yuan, Hong Wei, Zeyuan Huang, Haiqiao Wei, Siew Hwa Chan e Lei Zhou. "High-pressure injection or low-pressure injection for a direct injection hydrogen engine?" International Journal of Hydrogen Energy 59 (marzo 2024): 383–89. http://dx.doi.org/10.1016/j.ijhydene.2024.02.018.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

3

Navarro, C., R. Fernández-Escobar e M. Benlloch. "A Low-pressure, Trunk-injection Method for Introducing Chemical Formulations into Olive Trees". Journal of the American Society for Horticultural Science 117, n. 2 (marzo 1992): 357–60. http://dx.doi.org/10.21273/jashs.117.2.357.

Testo completo

Abstract (sommario):

A low-pressure injection method for introducing chemical formulations into trees is presented. The apparatus consists of a plastic injector and a tube providing a pressure of 60 to 80 kPa, which is below the injurious level for the xylem. The efficiency of the method was determined by injecting PTS, a marker of apoplastic flux dye solutions, and rubidium chloride into young trees, main scaffolds, or tree trunks. The depth of the hole drilled) and the number of injections necessary to distribute the solutions was also determined. The injected solutions moved mainly upward through the older rings of the xylem, suggesting that uptake is directly controlled by the transpiration rate. A single injection was enough to distribute solutions in scaffolds with a diameter of 8 cm, but two injections were necessary for 17-cm-diameter trunks. According to the results, the injection method was effective in introducing chemicals into olive (Olea europaea L.) trees. The method is easy to use, safe and economical and does not involve special equipment. Chemical name used: trisodium, 3-hydroxi-5,8,10-pyrenetrisulfonate (PTS).

Gli stili APA, Harvard, Vancouver, ISO e altri

4

Chen, Tao Ping, e Xian Xi Su. "Experimental Study of the Effect of Injection Different Kinds of Water on Extra Low Permeability Reservoir". Advanced Materials Research 968 (giugno 2014): 206–10. http://dx.doi.org/10.4028/www.scientific.net/amr.968.206.

Testo completo

Abstract (sommario):

The experiment study effect of injection different kinds of water on extra low permeability reservoir of Yushulin Oilfield. In the condition of actual temperature and pressure of the reservoir, through the experimental study the effect of injection different kinds of water on extra low permeability core. Experiments include injecting clean water, injecting clean water with scale inhibitor, injecting traditional treated sewage, injecting deep treated sewage, injecting deep treated sewage with scale inhibitor. The experimental results show that: Long term injecting clean water and clean water with scale inhibitor are harmless to core; Injecting traditional treated sewage, high content of oil and impurity bring injection pressure go up, the permeability of core down sharply; Injecting deep treated (aeration + flotation (PAC+PAM) + filtration + ultra filtration (FeCl3)) sewage must be added scale inhibitor, otherwise injection pressure continuously increase, permeability of the core continuously decrease, which seriously affect injection water.

Gli stili APA, Harvard, Vancouver, ISO e altri

5

Jeftić, Marko, Zhenyi Yang, Graham T. Reader e Ming Zheng. "Fuel efficiency analysis and peak pressure rise rate improvement for neat n-butanol injection strategies". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 231, n. 1 (5 agosto 2016): 50–65. http://dx.doi.org/10.1177/0954407016632141.

Testo completo

Abstract (sommario):

Engine tests were conducted to investigate the efficiency and the peak pressure rise rate performance of different fuel injection strategies for the direct injection of neat n-butanol in a compression ignition engine. Three different strategies were tested: a single-shot injection; a pilot injection; a post-injection. A single-shot injection timing sweep revealed that early injections had the highest indicated efficiency while late injections reduced the peak pressure rise rate at the cost of a slightly reduced thermal efficiency. Delayed single-shot injections also had increased emissions of nitrogen oxides, total hydrocarbon and carbon monoxide. Addition of a pilot injection had a negative effect on the peak pressure rise rate. Because of the low cetane number of butanol and the relatively lean and well-premixed air–fuel mixture, the pilot injection failed to autoignite and instead ignited simultaneously with the main injection. This resulted in slightly increased peak pressure rise rates and significantly increased unburned butanol hydrocarbon emissions. Conversely, the use of an early post-injection produced a noticeable engine power output and allowed the main injection to be shortened and the peak pressure rise rate to be substantially reduced. However, relatively early post-injections slightly reduced the indicated efficiency and increased the nitrogen oxide emissions and the carbon monoxide emissions compared with the single-shot injection strategy. These results recommended the use of a single-shot injection for low loads and medium loads owing to a superior thermal efficiency and suggested that the application of a post-injection may be more suited to high-load conditions because of the substantially reduced peak pressure rise rates.

Gli stili APA, Harvard, Vancouver, ISO e altri

6

Liu, Mingyang, Hu Wen, Shixing Fan, Zhenping Wang, Jinbiao Fei, Gaoming Wei, Xiaojiao Cheng e Hu Wang. "Experimental Study of CO2-ECBM by Injection Liquid CO2". Minerals 12, n. 3 (26 febbraio 2022): 297. http://dx.doi.org/10.3390/min12030297.

Testo completo

Abstract (sommario):

Coal mine gas disasters have severely restricted production safety. Improving gas extraction efficiency can effectively reduce disasters. Scholars have confirmed that CO2 successfully displaces coal seam CH4. This study conducted displacement and in situ experiments and compared gas drainage under different injection pressures. The displacement experiments indicated that CH4 production rates increased under increased pressures while the displacement ratios decreased. The pressure had a positive effect on sweep efficiency. The in situ experiment showed that CH4 and CO2 concentration trends in the inspection hole remained consistent. Through observing the data of the original and inspection holes, the average gas drainage concentration during low- and medium-pressure injections increased by 0.61 times and 1.17 times, respectively. The low-pressure average gas drainage scalar was increased by 1.08 times. During the medium-pressure injection, the average gas drainage purity increased by 1.94 times. The diffusion ranges of CO2 under low- and medium-pressure injections were 20–25 m and 25–30 m, respectively. The sweep efficiency of medium-pressure injection was 26% better than that of the low-pressure injection, with average pressures of 2.8 MPa and 1.4 MPa, respectively, for sweep efficiency. This study proposes an effective method for improving coal mine gas drainage efficiency.

Gli stili APA, Harvard, Vancouver, ISO e altri

7

JIA, Lidong. "Experiment of Low-pressure Injection Using Methanol". Journal of Mechanical Engineering 48, n. 20 (2012): 153. http://dx.doi.org/10.3901/jme.2012.20.153.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

8

Shaffer, Peter T. B. "The Advantage of Low Pressure Injection Molding". Materials Technology 8, n. 3-4 (marzo 1993): 57–59. http://dx.doi.org/10.1080/10667857.1993.11784939.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

9

Gonçalves, Aparecido Carlos. "Metallic powder injection molding using low pressure". Journal of Materials Processing Technology 118, n. 1-3 (dicembre 2001): 193–98. http://dx.doi.org/10.1016/s0924-0136(01)00916-5.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

10

HORIBA, Toshinaka, Nobushige TAMAKI e Masanori SHIMIZU. "Fundamental Study of Low Pressure Injection Nozzle". Proceedings of Conference of Chugoku-Shikoku Branch 2002.40 (2002): 165–66. http://dx.doi.org/10.1299/jsmecs.2002.40.165.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

11

Krindges, Israel, Raquel Andreola, Cláudio A. Perottoni e Janete E. Zorzi. "Low-Pressure Injection Molding of Ceramic Springs". International Journal of Applied Ceramic Technology 5, n. 3 (maggio 2008): 243–48. http://dx.doi.org/10.1111/j.1744-7402.2008.02226.x.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

12

Lamarre, Simon G., Vincent Demers e Jean-François Chatelain. "Low-pressure powder injection molding using an innovative injection press concept". International Journal of Advanced Manufacturing Technology 91, n. 5-8 (7 gennaio 2017): 2595–605. http://dx.doi.org/10.1007/s00170-016-9889-1.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

13

Yun, H., e R. D. Reitz. "Combustion optimization in the low-temperature diesel combustion regime". International Journal of Engine Research 6, n. 5 (1 ottobre 2005): 513–24. http://dx.doi.org/10.1243/146808705x30576.

Testo completo

Abstract (sommario):

A microgenetic algorithm (μGA) code was applied to optimize experimentally an HSDI single-cylinder diesel engine equipped with a common rail fuel-injection system in order to reduce NOx, soot, and b.s.f.c. simultaneously. Four control factors were used, namely, start-of-injection (SOI) timing, intake boost pressure level, cooled exhaust gas recirculation (EGR) rate, and fuel-injection pressure. The search space was designed to be within the experimental capabilities of the engine and control system. The engine testing was done at 1550 r/min, and 25 per cent load. The optimum results showed significant improvements for the NOx and soot emissions. Through analysis of the combustion characteristics, the mechanisms of emission reduction were revealed. The optimum featured a long ignition delay due to retarded SOI timing, and low combustion temperatures as a result of high EGR rates. The resulting long time for mixing and low temperatures helps suppress soot formation. To explore further the effect of mixing on emissions in the low-temperature combustion regime, factors that enhance turbulent mixing rates, including the use of high injection pressures and post injections were examined. The results show that optimal post injections are useful further to reduce emissions when they feature a short injection pulse with an optimal dwell time between injections.

Gli stili APA, Harvard, Vancouver, ISO e altri

14

Zhang, Rongrong, e Daifen Chen. "Investigation of Diesel Spray Characteristics in Low-temperature and Low-pressure Conditions". Bulletin of Science and Practice 10, n. 5 (15 maggio 2024): 383–96. http://dx.doi.org/10.33619/2414-2948/102/48.

Testo completo

Abstract (sommario):

This study investigates the influence of altitude and injection pressure on diesel fuel spray characteristics, aiming to optimize diesel usage in high-altitude conditions. Experiments were conducted at three altitude levels (plains, 1670 m, and 2400 m) with corresponding atmospheric pressures and temperatures, alongside six injection pressures ranging from 50 MPa to 100 MPa. The investigation focused on key spray parameters: equivalence ratio, spray penetration velocity, turbulence kinetic energy, evaporation rate, spray penetration distance, and Sauter Mean Diameter (SMD). Findings indicate that increased injection pressure enhances spray penetration velocity, evaporation rate, and turbulence kinetic energy, while reducing SMD, irrespective of altitude. Conversely, higher altitudes were associated with increased spray penetration speed, larger SMD, decreased evaporation rate, increased turbulence, and a higher equivalence ratio. The study concludes that both altitude and injection pressure significantly impact diesel spray characteristics, providing essential theoretical support for the application and optimization of diesel fuels in varied altitude conditions.

Gli stili APA, Harvard, Vancouver, ISO e altri

15

Kang, Seungwoo, Sanguk Lee e Choongsik Bae. "Effects of Multi-Stage Split Injection on Efficiency and Emissions of Light-Duty Diesel Engine". Energies 15, n. 6 (18 marzo 2022): 2219. http://dx.doi.org/10.3390/en15062219.

Testo completo

Abstract (sommario):

The efficiency of light-duty diesel engines should be improved for further emissions regulation. Multi-stage split injection with five injection events was investigated for improvement in efficiency at low-load conditions. The injection timing and quantity were adjusted to achieve a smooth in-cylinder pressure rise and continuous heat release. The multi-stage split injection was compared to injection strategies involving two-pilot and single-main injections. A 0.5 L single-cylinder diesel engine experiment was conducted under low-load conditions. Two multi-stage split injection processes with different combustion phases were developed. The multi-stage split injections yielded a smooth in-cylinder pressure trace and a lower peak heat release rate than the two-pilot injection process. The combustion duration was shorter for multi-stage split injection with an advanced combustion phase, and the fuel consumption was reduced by 1.78% with lower heat transfer, exhaust heat, and combustion loss. The multi-stage split injection flame penetration was shorter than the two-pilot injections. The shorter flame penetration and lower tip velocity reduced the heat transfer to the combustion chamber. The PM emissions were also reduced by 30% under the same NOx emissions, because increased PM oxidation and divided fuel injection prevented flame diffusion and improved air utilization.

Gli stili APA, Harvard, Vancouver, ISO e altri

16

Li, Yuan, Jinxiang Liu, Weiqing Huang e Nana Wang. "Effect of In-Cylinder Low-Pressure Direct Injection Strategy on the Atomization and Combustion Process of a Small-Scaled Gasoline Wankel Rotary Engine". International Journal of Energy Research 2023 (6 febbraio 2023): 1–14. http://dx.doi.org/10.1155/2023/3716468.

Testo completo

Abstract (sommario):

To solve the problem of poor atomization and combustion in a small-scaled gasoline Wankel rotary engine (WRE) with low-pressure port injection mode, the numerical simulation was used to optimize the injection strategy. Firstly, the effects of in-cylinder temperature and pressure on gasoline atomization characteristics were studied, and the optimal injection timing was determined. Based on this, the influence of injection position, injection angle, and installation direction on the atomization, fuel-air mixing, and combustion processes of low-pressure direct injection (DI) small-scaled gasoline WRE was investigated. The results show that the injection angle is a key factor in determining the gasoline atomization characteristics. Injecting along the direction of rotor rotation causes the impingement between fuel bundle and combustion chamber pocket, resulting in the smaller Sauter mean diameter (SMD) and liquid penetration length (LPL). The installation direction of nozzle plays an important role in the airflow movement. When the nozzle is vertical-installed, the airflow repeatedly crosses to form multiple eddies, making the fuel to move more easily towards the front of combustion chamber. When the nozzle is parallel-installed at the lower edge of the installing zone and injecting along the direction of rotor rotation, the peak in-cylinder pressure is the largest and increased by 21% compared to the original port injection. By this injection strategy, the problem of incomplete combustion for the studied small-scaled gasoline WRE could be almost completely solved.

Gli stili APA, Harvard, Vancouver, ISO e altri

17

Soares, J. P. "Low-pressure injection moulding of stainless steel powders". Metal Powder Report 57, n. 4 (aprile 2002): 42. http://dx.doi.org/10.1016/s0026-0657(02)80156-4.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

18

Momeni, Vahid, Margarete Hufnagl, Zahra Shahroodi, Joamin Gonzalez-Gutierrez, Stephan Schuschnigg, Christian Kukla e Clemens Holzer. "Research Progress on Low-Pressure Powder Injection Molding". Materials 16, n. 1 (30 dicembre 2022): 379. http://dx.doi.org/10.3390/ma16010379.

Testo completo

Abstract (sommario):

Powder injection molding (PIM) is a well-known technique to manufacture net-shaped, complicated, macro or micro parts employing a wide range of materials and alloys. Depending on the pressure applied to inject the feedstock, this process can be separated into low-pressure (LPIM) and high-pressure (HPIM) injection molding. Although the LPIM and HPIM processes are theoretically similar, all steps have substantial differences, particularly feedstock preparation, injection, and debinding. After decades of focusing on HPIM, low-viscosity feedstocks with improved flowability have recently been produced utilizing low-molecular-weight polymers for LPIM. It has been proven that LPIM can be used for making parts in low quantities or mass production. Compared to HPIM, which could only be used for the mass production of metallic and ceramic components, LPIM can give an outstanding opportunity to cover applications in low or large batch production rates. Due to the use of low-cost equipment, LPIM also provides several economic benefits. However, establishing an optimal binder system for all powders that should be injected at extremely low pressures (below 1 MPa) is challenging. Therefore, various defects may occur throughout the mixing, injection, debinding, and sintering stages. Since all steps in the process are interrelated, it is important to have a general picture of the whole process which needs a scientific overview. This paper reviews the potential of LPIM and the characteristics of all steps. A complete academic and research background survey on the applications, challenges, and prospects has been indicated. It can be concluded that although many challenges of LPIM have been solved, it could be a proper solution to use this process and materials in developing new applications for technologies such as additive manufacturing and processing of sensitive alloys.

Gli stili APA, Harvard, Vancouver, ISO e altri

19

Millán, A. J., M. Bravo, R. Moreno e M. I. Nieto. "Moldeo por inyección a baja presión de suspensiones cerámicas". Boletín de la Sociedad Española de Cerámica y Vidrio 38, n. 2 (30 aprile 1999): 93–99. http://dx.doi.org/10.3989/cyv.1999.v38.i2.965.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

20

Wu, Qiong. "Analysis of reducing pressure and increasing injection in high pressure water injection block of low permeability reservoir". E3S Web of Conferences 358 (2022): 02028. http://dx.doi.org/10.1051/e3sconf/202235802028.

Testo completo

Abstract (sommario):

The plugging phenomenon near the well zone of oil injection well will seriously affect the water injection development of oil field, and then affect the exploitation of oil resources. The water injection development of low permeability reservoir is affected by various factors. Due to the large difference between layers and the serious interference between layers, the physical property of oil layer is relatively poor, and the water injection pressure shows a trend of increasing year by year, which has a great impact on the development of oil resources. As the oilfield development benefit is not ideal, it is necessary to take reasonable measures to reduce the pressure of water injection to ensure the effect of water injection to improve the recovery of the reservoir. At present, the technology has been mature, which can reduce the pressure of water injection and ensure the oil recovery rate. The application in several oil Wells has verified the correctness of this conclusion.

Gli stili APA, Harvard, Vancouver, ISO e altri

21

Gao, Tongyang, Shui Yu, Tie Li e Ming Zheng. "Impacts of multiple pilot diesel injections on the premixed combustion of ethanol fuel". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 232, n. 6 (3 luglio 2017): 738–54. http://dx.doi.org/10.1177/0954407017706858.

Testo completo

Abstract (sommario):

Engine experiments were carried out to study the impact of multiple pilot injections of a diesel fuel on dual-fuel combustion with a premixed ethanol fuel, using compression ignition. Because of the contrasting volatility and the reactivity characteristics of the two fuels, the appropropriate scheduling of pilot diesel injections in a high-pressure direct-injection process is found to be effective for improving the clean and efficient combustion of ethanol which is premixed with air using a low-pressure port injection. The timing and duration of each of the multiple pilot injections were investigated, in conjunction with the use of exhaust gas recirculation and intake air boosting to accommodate the variations in the engine load. For correct fuel and air management, an early pilot injection of fuel acted effectively as the reactivity improver to the background ethanol, whereas a late pilot injection acted deterministically to initiate combustion. The experimental results further revealed a set of pilot injection strategies which resulted in an increased ethanol ratio, thereby reducing the emission reductions while retaining a moderate pressure rise rate during combustion.

Gli stili APA, Harvard, Vancouver, ISO e altri

22

Rahimi Boldaji, Mozhgan, Aimilios Sofianopoulos, Sotirios Mamalis e Benjamin Lawler. "Computational fluid dynamics investigations of the effect of water injection timing on thermal stratification and heat release in thermally stratified compression ignition combustion". International Journal of Engine Research 20, n. 5 (30 aprile 2018): 555–69. http://dx.doi.org/10.1177/1468087418767451.

Testo completo

Abstract (sommario):

Advanced combustion concepts, like homogeneous charge compression ignition, are limited by their narrow operating range, which stems from a lack of control over the heat release process. This study explores a new advanced combustion mode, called thermally stratified compression ignition, which uses a direct water injection event to control the heat release process in low-temperature combustion. A three-dimensional computational fluid dynamics model coupled with detailed chemical kinetics is used to better understand the effects of direct water injection on thermal stratification in the cylinder and the resulting heat release process. Previous results showed that increasing the injection pressure results in a significantly broader temperature distribution due to increased evaporative cooling. In this way, direct water injection can control low-temperature combustion heat release and extend significantly the operable load range. In this study, simulations were performed over a range of start of injection timings in order to determine its effect on thermal stratification and heat release. The results show that for both low and high injection pressures advancing the start of water injection results in increased thermal stratification and reduced peak pressure and heat release rate for injections occurring after −60 °CAD. Before −60 °CAD, advancing the water injection has a varied effect on thermal stratification and heat release depending on the injection pressure and mass of the injected water.

Gli stili APA, Harvard, Vancouver, ISO e altri

23

Cui, Chuanzhi, Guobiao Wang e Shuiqingshan Lu. "Study on the influencing factors of productivity under pressure drive development in low permeability reservoir". E3S Web of Conferences 375 (2023): 01050. http://dx.doi.org/10.1051/e3sconf/202337501050.

Testo completo

Abstract (sommario):

The productivity of low-permeability reservoirs is affected by multiple factors. After the development of water injection by pressure drive, it will also be affected by factors such as construction, resulting in large differences in the productivity of different oil wells. According to reservoir engineering knowledge, the factors affecting the productivity of pressure drive water injection development are preliminarily determined. The conceptual model of pressure drive water injection development of low permeability reservoir is established by numerical simulation method. Combined with orthogonal design, the main control factors of pressure drive water injection development productivity are determined. The main control factors include injection production well spacing, water injection volume of pressure drive measures, water content before pressure drive, porosity, and quantitative analysis of the main control factors. Through correct analysis and evaluation of these factors, it provides guiding significance for the productivity prediction of pressure drive water injection development in low permeability reservoirs and the optimization of pressure drive water injection scheme.

Gli stili APA, Harvard, Vancouver, ISO e altri

24

Wang, Huping, Zhao Wang, Haikui Yin, Chao Jin, Xiaogang Zhang e Langtao Liu. "CO2 Flow Characteristics in Macro-Scale Coal Sample: Effect of CO2 Injection Pressure and Buried Depth". Sustainability 15, n. 10 (14 maggio 2023): 8002. http://dx.doi.org/10.3390/su15108002.

Testo completo

Abstract (sommario):

Experimental studies have confirmed the permeability reduction of coal samples upon the adsorption of CO2. However, these studies were carried out under limited experimental conditions. In this study, CO2 flow behaviors in a macro-scale coal sample were numerically simulated using a coupled gas flow, mechanical deformation, and sorption-induced deformation finite element model. The simulation results show that the effect of the reduction of effective stress on the enhancement of permeability is greater than the negative effect of permeability reduction due to CO2 adsorption for low injection pressures. CO2 pressure development in the sample increases with increasing injection pressure due to the enhanced advection flux for sub-critical CO2 injections, while for super-critical CO2 injections, CO2 pressure development, as well as concentrations in the sample, decreases compared to sub-critical CO2 injections because of greater density and viscosity of super-critical CO2 as well as coal matrix swelling induced by the adsorption of super-critical CO2. Increasing axial stress (buried depth) obstructs CO2 migration in the sample due to the increased effective stress, and this effect is more influential for low injection pressures, which indicates that high CO2 injection pressures are preferred for CO2 sequestration in deep coal seams.

Gli stili APA, Harvard, Vancouver, ISO e altri

25

Yoshida, Kenji, Eri Tanaka, Hiroyoshi Kawaai e Shinya Yamazaki. "Effect of Injection Pressure of Infiltration Anesthesia to the Jawbone". Anesthesia Progress 63, n. 3 (1 settembre 2016): 131–38. http://dx.doi.org/10.2344/15-00024.1.

Testo completo

Abstract (sommario):

To obtain effective infiltration anesthesia in the jawbone, high concentrations of local anesthetic are needed. However, to reduce pain experienced by patients during local anesthetic administration, low-pressure injection is recommended for subperiosteal infiltration anesthesia. Currently, there are no studies regarding the effect of injection pressure on infiltration anesthesia, and a standard injection pressure has not been clearly determined. Hence, the effect of injection pressure of subperiosteal infiltration anesthesia on local anesthetic infiltration to the jawbone was considered by directly measuring lidocaine concentration in the jawbone. Japanese white male rabbits were used as test animals. After inducing general anesthesia with oxygen and sevoflurane, cannulation to the femoral artery was performed and arterial pressure was continuously recorded. Subperiosteal infiltration anesthesia was performed by injecting 0.5 mL of 2% lidocaine containing 1/80,000 adrenaline, and injection pressure was monitored by a pressure transducer for 40 seconds. After specified time intervals (10, 20, 30, 40, 50, and 60 minutes), jawbone and blood samples were collected, and the concentration of lidocaine at each time interval was measured. The mean injection pressure was divided into 4 groups (100 ± 50 mm Hg, 200 ± 50 mm Hg, 300 ± 50 mm Hg, and 400 ± 50 mm Hg), and comparison statistical analysis between these 4 groups was performed. No significant change in blood pressure during infiltration anesthesia was observed in any of the 4 groups. Lidocaine concentration in the blood and jawbone were highest 10 minutes after the infiltration anesthesia in all 4 groups and decreased thereafter. Lidocaine concentration in the jawbone increased as injection pressure increased, while serum lidocaine concentration was significantly lower. This suggests that when injection pressure of subperiosteal infiltration anesthesia is low, infiltration of local anesthetic to the jawbone may be reduced, while transfer to oral mucosa and blood may be increased.

Gli stili APA, Harvard, Vancouver, ISO e altri

26

Zhu, Xiulan, Yanlong Ran e Yidong Yuan. "Research on optimization of development technology policy for low-permeability and low-pressure reservoir in Yangbaishan Block". E3S Web of Conferences 118 (2019): 01029. http://dx.doi.org/10.1051/e3sconf/201911801029.

Testo completo

Abstract (sommario):

There are poor physical properties and insufficient natural energy in the low-permeability and low-pressure reservoir of the Yangbaishan Block. Early this reservoir was mined by natural energy with a serious producing energy deficit. Subsequently, it was developed with mild water injection. During the water injection development, water quickly slid into the oil well along the crack, oil production decreased sharply and water content increased rapidly in the oil well, the water flooded well and the ineffective well gradually increased. Therefore, based on the reservoir geological characteristics, principle of injection and production balance is used to optimize reasonably for the development technology policy. Research indicates that the square inverted nine spot flooding pattern is recommended with a reasonable injection well direction of NE 72°and technical well spacing of 150 m. Reasonable injection-production ratio should be 2.16, reasonable technical well pattern density is 23 wells per square kilometer, and the average daily water injection rate of single well should be 11 m3. When injection-production system and injection proration are improved, water drive controlled degree is expected to increase by 16 %. This research can provide reference for the efficient development and safety management of other similar reservoirs.

Gli stili APA, Harvard, Vancouver, ISO e altri

27

Banji, Titilope Ibukun, Gregg Arney e Daniel B. Olsen. "Fuel Injection Optimization for Large-Bore Two-Stroke Natural-Gas Engines". Energies 18, n. 3 (29 gennaio 2025): 624. https://doi.org/10.3390/en18030624.

Testo completo

Abstract (sommario):

Recent methane emissions regulations present a challenge for the large-bore, natural-gas-fueled engines used at over 1700 compression stations across the US. Poor air–fuel mixing in the main combustion chamber of these engines results in low combustion efficiency and the resulting methane emissions. High-pressure fuel injection is believed to be a significant development in improving air–fuel mixing in natural-gas engine combustion chambers. This study aims to determine the sensitivity of in-cylinder mixing to injection pressures using Computational Fluid Dynamics (CFD) simulations, determine the limits of high-pressure fuel injection, and explore high-momentum low-pressure fuel injection. The engine, modeled using Converge Studio for CFD, was a Cooper-Bessemer large-bore, four-cylinder, GMV-4TF spark-ignited natural-gas engine with direct injection. The model was simulated for four sets of configured cases—baseline; ideal mixing; injection pressure variation; and low-pressure, high-momentum injection. The results show that fuel injection at 700 psi and −115 degrees BTDC gives the best in-cylinder mixing and improved mixing, potentially reducing methane emissions by half. The optimal timing for the injection at different injection pressures was determined. The level of mixing in low-pressure fuel-injection systems was also improved by the high-momentum fuel injector design. It was concluded that mixing can be further improved in integral gas compressor engines through fuel injection optimization.

Gli stili APA, Harvard, Vancouver, ISO e altri

28

Virt, Márton, Gergely Granovitter, Máté Zöldy, Ádám Bárdos e Ádám Nyerges. "Multipulse Ballistic Injection: A Novel Method for Improving Low Temperature Combustion with Early Injection Timings". Energies 14, n. 13 (22 giugno 2021): 3727. http://dx.doi.org/10.3390/en14133727.

Testo completo

Abstract (sommario):

Nowadays, increasingly stricter regulations on emission reduction are inducing rapid developments in combustion science. Low-temperature combustion (LTC) is an advanced combustion technology that increases an engine’s thermal efficiency and even provides low emissions of nitrogen oxides (NOx) and particulate matter (PM). The technology often uses early direct injections to achieve sufficient mixture homogeneity. This leads to increasing wall wetting and lower combustion efficiency. This paper introduces the Multipulse ballistic injection (MBI) method to improve combustion with early injection timings. The research was carried out in a four-cylinder medium-duty diesel engine with high-pressure exhaust gas recirculation (HP-EGR). The investigation was divided into two experiments. In the first experiment, MBI was examined without EGR, and in the second, EGR was applied to study its effects. It was found that the MBI strategy decreased wall wetting and increased homogeneity and the indicated mean effective pressure (IMEP) at early injection angles.

Gli stili APA, Harvard, Vancouver, ISO e altri

29

Aldila, Migel, Iwan Febrianto, Akhmad Sudirman Saputra, Purnama Timur M.S e Ninik Purwatiningsih. "The Effect of Carbon Steel Pipeline Deterioration to Water Injection Quality and Pressure Drop in Tanjung Waterflood Injection Plant." Scientific Contributions Oil and Gas 43, n. 1 (7 agosto 2020): 1–6. http://dx.doi.org/10.29017/scog.43.1.389.

Testo completo

Abstract (sommario):

In Tanjung, South Kalimantan, PT Pertamina EP (PEP) use secondary recovery (waterflood injection) for its technique for oil lifting. Low permeability reservoir condition make quality of water injection must be comply with low permeability reservoir requirement and the pressure injection must be around 1400 psig. In the common PEP injection plant, carbon steel pipeline is still used. Flakes accumulation and trapped oil could occur along with the deterioration of carbon steel pipeline. This matter can make the quality of requirements of injection water become worst. There were four data were analyzed; Oil content, TSS (Total Suspended Solid), Turbidity and Total Iron. The sample was taken at discharge pump and one of the injections well during 6 months. Averagely the result of value of total iron, turbidity and oil content in injection well are bigger than discharge pump while TSS has little fluctuation. In conclusion, deterioration carbon steel pipeline has effect to reduce quality water injection become worst and effect of roughness of pipeline due to carbon steel deterioration can make the pressure drop is higher in accordance with the length.

Gli stili APA, Harvard, Vancouver, ISO e altri

30

Jeong, Eunju, Sean O’Byrne, In-Seuck Jeung e A. F. P. Houwing. "The Effect of Fuel Injection Location on Supersonic Hydrogen Combustion in a Cavity-Based Model Scramjet Combustor". Energies 13, n. 1 (1 gennaio 2020): 193. http://dx.doi.org/10.3390/en13010193.

Testo completo

Abstract (sommario):

Supersonic combustion experiments were performed using three different hydrogen fuel-injection configurations in a cavity-based model scramjet combustor with various global fuel–air equivalence ratios. The configurations tested were angled injection at 15° to the flow direction upstream of the cavity, parallel injection from the front step, and upstream injection from the rear ramp. Planar laser-induced fluorescence of the hydroxyl radical and time-resolved pressure measurements were used to investigate the flow characteristics. Angled injection generated a weak bow shock in front of the injector and recirculation zone to maintain the combustion as the equivalence ratio increased. Parallel and upstream injections both showed similar flame structure over the cavity at low equivalence ratio. Upstream injection enhanced the fuel diffusion and enabled ignition with a shorter delay length than with parallel injection. The presence of a flame near the cavity was determined while varying the fuel injection location, the equivalence ratio, and total enthalpy of the air flow. The flame characteristics agreed with the correlation plot for the stable flame limit of non-premixed conditions. The pressure increase in the cavity for reacting flow compared to non-reacting flow was almost identical for all three configurations. More than 300 mm downstream of the duct entrance, averaged pressure ratios at low global equivalence ratio were similar for all three injection configurations.

Gli stili APA, Harvard, Vancouver, ISO e altri

31

Canakci, M., e R. D. Reitz. "Experimental optimization of a direct injection homogeneous charge compression ignition gasoline engine using split injections with fully automated microgenetic algorithms". International Journal of Engine Research 4, n. 1 (1 febbraio 2003): 47–60. http://dx.doi.org/10.1243/146808703762826642.

Testo completo

Abstract (sommario):

Homogeneous charge compression ignition (HCCI) is receiving attention as a new low-emission engine concept. Little is known about the optimal operating conditions for this engine operation mode. Combustion under homogeneous, low equivalence ratio conditions results in modest temperature combustion products, containing very low concentrations of NOx and particulate matter (PM) as well as providing high thermal efficiency. However, this combustion mode can produce higher HC and CO emissions than those of conventional engines. An electronically controlled Caterpillar single-cylinder oil test engine (SCOTE), originally designed for heavy-duty diesel applications, was converted to an HCCI direct injection (DI) gasoline engine. The engine features an electronically controlled low-pressure direct injection gasoline (DI-G) injector with a 60° spray angle that is capable of multiple injections. The use of double injection was explored for emission control and the engine was optimized using fully automated experiments and a microgenetic algorithm optimization code. The variables changed during the optimization include the intake air temperature, start of injection timing and the split injection parameters (per cent mass of fuel in each injection, dwell between the pulses). The engine performance and emissions were determined at 700 r/min with a constant fuel flowrate at 10 MPa fuel injection pressure. The results show that significant emissions reductions are possible with the use of optimal injection strategies.

Gli stili APA, Harvard, Vancouver, ISO e altri

32

Ikegami, R. A., e B. de M. Purquerio. "The Low Pressure Injection Moulding of Stainless Steel Powder". Key Engineering Materials 189-191 (febbraio 2001): 467–72. http://dx.doi.org/10.4028/www.scientific.net/kem.189-191.467.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

33

Zampieron, J. V., J. P. Soares, F. Mathias, J. L. Rossi e Francisco Ambrozio Filho. "Low Pressure Powder Injection Moulding of Stainless Steel Powders". Key Engineering Materials 189-191 (febbraio 2001): 610–15. http://dx.doi.org/10.4028/www.scientific.net/kem.189-191.610.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

34

Germanaud, Jacques, e Andr?? Rousseau. "Necrosis After Low-Pressure Injection Injury of the Hand". Journal of Occupational and Environmental Medicine 35, n. 7 (luglio 1993): 655. http://dx.doi.org/10.1097/00043764-199307000-00007.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

35

Schmidt, Stephan, Alexander Trattner, Helmut Eichlseder e Roland Kirchberger. "Combustion Processes for a low pressure gasoline direct injection". MTZ worldwide 72, n. 7-8 (24 giugno 2011): 72–78. http://dx.doi.org/10.1365/s38313-011-0080-7.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

36

Kim, Jung Hyeun, Heinz Fissan, Christof Asbach, Se-Jin Yook e David Y. H. Pui. "Speed-controlled particle injection into a low-pressure system". Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films 24, n. 2 (marzo 2006): 229–34. http://dx.doi.org/10.1116/1.2165660.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

37

Vučković, Ilvana, Admir Hadžić, Faruk Dilberović, Amela Kulenović, Zakira Mornjaković, Irfan Zulić, Kučuk-Alija Divanović, Eldan Kapur, Esad Čosović e Alma Voljevica. "Detection of neurovascular structures using injection pressure in blockade of brachial plexus in rat". Bosnian Journal of Basic Medical Sciences 5, n. 3 (20 agosto 2005): 79–85. http://dx.doi.org/10.17305/bjbms.2005.3276.

Testo completo

Abstract (sommario):

In the last few decades there has been a great development of regional anesthesia; all the postulates are defined and all the techniques of usage are perfected. However, like any other medical procedure, the block of brachial plexus carries a risk of certain unwanted complications, like possible intraneural and intravascular injections. The reason for great discrepancy between the injury of brachial plexus and other periphery nerves while performing the nerve blockade is the frequent usage of this block, but also the specific proximity of neurovascular structures in axilla. The purpose of this work is to determine the values of pressures which appear in paraneural, intraneural and intravascular injection applications of local anesthetic, and to compare those values in order to avoid cases of intraneural and in-travascular injections in clinical practice with consequential complications. In experimental study there have been used 12 Wistar rats of both genders. After anesthesia with ether and midhumeral access to the neurovascular structures in axilla, the injection of 2% lidocain with epinephrine was performed with the help of automatic syringe charger. The needle was at first placed paraneural, and then also intraneural and intravascular. During every application the pressure values were monitored using the manometer, and then they were analyzed by special software program. All paraneural injections resulted with the pressure between 13,96-27,92 kPa. The majority of intraneural injections were combined with the injection pressure greater than 69,8 kPa, while the intravascular injections were combined with injection pressure less than 6,98 kPa. Based on the available data it can be noticed that so far none of the methods of prevention from unwanted complications of regional anesthesia can insure the avoidance of intraneural and intravascular injection of local anesthetic. Based on our research it is obvious that the measuring of pressure during the nerve blockade is very important in order to decrease the risk of neurological and possible systematic complications. It is also clear that a small, mobile, and financially quite available apparatus for pressure measurement can help in differentiation between paraneural, intra-neural and intravascular injection. Avoiding high injection pressure prevents from lodging the needle into intraneural space, while avoiding a very low injection pressure prevents from lodging the needle into intravascular space followed by consequential complications. The usage of this apparatus can find its application in other blockades of periphery nerves, and in other branches of medicine as well.

Gli stili APA, Harvard, Vancouver, ISO e altri

38

He, Jin Gang, Kao Ping Song, Jing Yang, Bao Gang Sun, Si Chen e Sheng Jian Shu. "A Study of Influential Factors of Advance Water Injection in Extra-Low Permeability Reservoir". Applied Mechanics and Materials 487 (gennaio 2014): 255–58. http://dx.doi.org/10.4028/www.scientific.net/amm.487.255.

Testo completo

Abstract (sommario):

This paper study on the permeability, start-up pressure gradient and stress sensitivity of advance water injection in extra-low permeability reservoir in Fuyu Oil layer of Daqing Oilfield. Experimental results show that the reasonable formation pressure level should be at about 120% in the advance water injection experiment, advanced water injection in the the early stage have higher oil production, the water breakthrough, earlier than synchronous water injection has certain inhibitory effect of water cut rise; Under the premise of advance water injection can overcome the start-up pressure, the lower the level of the reservoir permeability, the higher improve recovery efficiency of the proportion; permeability retention rate increase by about 22% with 5×10-3μm2 core and effectively overcome the stress sensitivity of low permeability reservoir damage; Advanced water injection can overcome stress sensitivity and restoring formation pressure, all that influence the start-up pressure gradient, which significantly reduce the start-up pressure gradient.

Gli stili APA, Harvard, Vancouver, ISO e altri

39

Reddy, Ch Kesava, M. V. S. Murali Krishna, P. V. K. Murthy e T. Ratna Reddy. "Performance Evaluation of a Low-Grade Low-Heat-Rejection Diesel Engine with Crude Pongamia oil". ISRN Renewable Energy 2012 (15 marzo 2012): 1–10. http://dx.doi.org/10.5402/2012/489605.

Testo completo

Abstract (sommario):

Investigations are carried out to evaluate the performance of a low heat rejection (LHR) diesel engine with ceramic coated cylinder head [ceramic coating of thickness 500 microns is done on inside portion of cylinder head] with different operating conditions [normal temperature and pre-heated temperature] of crude Pongamia oil (CPO) with varied injection pressure and injection timing. Performance parameters and pollution levels are determined at various magnitudes of brake mean effective pressure. Combustion characteristics at peak load operation of the engine are measured with special pressure-crank angle software package. Conventional engine (CE) showed deteriorated performance, while LHR engine showed improved performance with CPO operation at recommended injection timing and pressure and the performance of both version of the engine is improved with advanced injection timing and at higher injection pressure when compared with CE with pure diesel operation. The optimum injection timing is 31°bTDC for conventional engine while it is 29°bTDC with LHR engine with vegetable oil operation. Peak brake thermal efficiency increased by 5%, smoke levels decreased by 2% and NOx levels increased by 40% with CPO operation on LHR engine at its optimum injection timing, when compared with pure diesel operation on CE at manufacturer’s recommended injection timing.

Gli stili APA, Harvard, Vancouver, ISO e altri

40

Zhang, Qi Han, Zi Yi Guo, Ji Peng, Ting Song Xiong e Shi Feng Xue. "Numerical Simulation of Pressure Distribution between Injection and Production Well in Low Permeability Reservoir". Advanced Materials Research 807-809 (settembre 2013): 2554–57. http://dx.doi.org/10.4028/www.scientific.net/amr.807-809.2554.

Testo completo

Abstract (sommario):

Considering the pressure-sensitive effect and threshold pressure gradient in low permeability reservoirs, a new mathematical model of the variable permeability for reservoir between injection and production well is established. The Garlerkin method is used to set up the finite element computation equations, and corresponding numerical simulation program is developed. The influence of Injection-production pressure, well spacing and hydraulic fracture are quantitative evaluation. The simulation results show that the pressure-sensitive effect and threshold pressure gradient has a strong influence on pressure distribution between injection and production wells. Establishing the effective driving pressure system is the key to improve well production of low permeability reservoir.

Gli stili APA, Harvard, Vancouver, ISO e altri

41

Ma, Qianqian, Hong Li, Kun Ji e Fengjun Huang. "Thermal-Hydraulic-Mechanical Coupling Simulation of CO2 Enhanced Coalbed Methane Recovery with Regards to Low-Rank but Relatively Shallow Coal Seams". Applied Sciences 13, n. 4 (17 febbraio 2023): 2592. http://dx.doi.org/10.3390/app13042592.

Testo completo

Abstract (sommario):

CO2 injection technology into coal seams to enhance CH4 recovery (CO2-ECBM), therefore presenting the dual benefit of greenhouse gas emission reduction and clean fossil energy development. In order to gaze into the features of CO2 injection’s influence on reservoir pressure and permeability, the Thermal-Hydraulic-Mechanical coupling mechanism of CO2 injection into the coal seam is considered for investigation. The competitive adsorption, diffusion, and seepage flowing of CO2 and CH4 as well as the dynamic evolution of fracture porosity of coal seams are considered. Fluid physical parameters are obtained by the fitting equation using MATLAB to call EOS software Refprop. Based on the Canadian CO2-ECBM project CSEMP, the numerical simulation targeting shallow low-rank coal is carried out, and the finite element method is used in the software COMSOL Multiphysics. Firstly, the direct recovery (CBM) and CO2-ECBM are compared, and it is confirmed that the injection of CO2 has a significant improvement effect on methane production. Secondly, the influence of injection pressure and temperature is discussed. Increasing the injection pressure can increase the pressure difference in the reservoir in a short time, so as to improve the CH4 production and CO2 storage. However, the increase in gas injection pressure will also lead to the rapid attenuation of near-well reservoir permeability, resulting in the weakening of injection capacity. Also, when the injection temperature increases, the CO2 concentration is relatively reduced, and the replacement effect on CH4 is weakened, resulting in a slight decrease in CBM production and CO2 storage.

Gli stili APA, Harvard, Vancouver, ISO e altri

42

Felayati, Frengki Mohamad, Dwisetiono, Hadi Prasutiyon e Betty Ariani. "Study on Natural Gas/Diesel Dual-fuel Engine Energy Ratio: Effect of Natural Gas Injection Parameters". IOP Conference Series: Earth and Environmental Science 1081, n. 1 (1 settembre 2022): 012038. http://dx.doi.org/10.1088/1755-1315/1081/1/012038.

Testo completo

Abstract (sommario):

Abstract Natural gas has been a promising demand for several years in Indonesia as a fuel for a diesel engine by converted into a natural gas/diesel dual-fuel engine. However, determining the energy ratio of the diesel and natural gas fuel is important due to the engine performance and emissions which affect the engine safety operation. This study presents the method to determine the natural gas and diesel fuel energy ratio on intake port natural gas injection mode through experiment. A direct injection diesel engine is converted to a natural gas/diesel dual-fuel engine by injecting natural gas into the intake port. The diesel injection parameters are unmodified for the experiment; besides the natural gas injection variations are studied to determine the energy ratio. Moreover, the engine is tested for low to high load conditions. However, natural gas injection duration, pressure, and injection timing variation affect the fuel energy ratio and indicated thermal efficiency (ITE). At low load, the optimum fuel energy ratio and ITE are achieved at a long injection duration (10 ms) and with advanced injection timing. Moreover, at high load, the optimum fuel energy ratio and ITE is achieved at high natural gas injection duration (12 ms), high injection pressure (3 bar), and advancing the injection timing.

Gli stili APA, Harvard, Vancouver, ISO e altri

43

Huang, Xiao Liang. "Reasonably Water Injection Time about Abnormal Pressure of Low Permeability Reservoir". Advanced Materials Research 601 (dicembre 2012): 134–38. http://dx.doi.org/10.4028/www.scientific.net/amr.601.134.

Testo completo

Abstract (sommario):

Abnormal pressure of low permeability reservoirs is a special reservoir, which have some characteristic : low permeability, strong stress sensitivity, complex pore structure, abnormal pressure. with the pressure decreasing about bottom-hole and reservoir, the formation of the rock pore space and permeability will decrease, and reservoir stress-sensitive phenomenon of serious. All these have brought greater difficulty for developing. in order to reasonable development of those reservoirs, maintain the formation energy is important, choose the reasonable injection timing is an important aspect. In this paper, taking abnormal pressure of low permeability reservoir as an example, studies variation law of abnormally pressure reservoir rock compressibility, porosity, stress sensitivity by experimental, Associated with the nature of the reservoir to determine a reasonable water injection time, and demonstrated by numerical simulation, finally proposed reasonable water injection timing about abnormal pressure of low-permeability reservoirs.

Gli stili APA, Harvard, Vancouver, ISO e altri

44

Canakci, M., e R. D. Reitz. "Effect of Optimization Criteria on Direct-Injection Homegeneous Charge Compression Ignition Gasoline Engine Performance and Emissions Using Fully Automated Experiments and Microgenetic Algorithms". Journal of Engineering for Gas Turbines and Power 126, n. 1 (1 gennaio 2004): 167–77. http://dx.doi.org/10.1115/1.1635395.

Testo completo

Abstract (sommario):

Homogeneous charge compression ignition (HCCI) is a new low-emission engine concept. Combustion under homogeneous, low equivalence ratio conditions results in modest temperature combustion products, containing very low concentrations of NOx and PM as well as providing high thermal efficiency. However, this combustion mode can produce higher HC and CO emissions than those of conventional engines. Control of the start of combustion timing is difficult with pre-mixed charge HCCI. Accordingly, in the present study charge preparation and combustion phasing control is achieved with direct injection. An electronically controlled Caterpillar single-cylinder oil test engine (SCOTE), originally designed for heavy-duty diesel applications, was converted to a direct-injection gasoline engine. The engine features an electronically controlled low-pressure direct injection-gasoline (DI-G) injector with a 60 deg spray angle that is capable of multiple injections. The use of double injection was explored for emission control, and the engine was optimized using fully automated experiments and a microgenetic algorithm optimization code. The variables changed during the optimization include the intake air temperature, start of injection timing, and the split injection parameters (percent mass of fuel in each injection, dwell between the pulses) using three different objective (merit) functions. The engine performance and emissions were determined at 700 rev/min with a constant fuel flow rate at 10 MPa fuel injection pressure. The results show the choice of merit or objective function (optimization goal) determines the engine performance, and that significant emission reductions can be achieved with optimal injection strategies. Merit function formulations are presented that minimized PM, HC, and NOx emissions, respectively.

Gli stili APA, Harvard, Vancouver, ISO e altri

45

Tan, Xiaohua, Jiajia Shi, Dong Hui, Qiu Li e Tingting Wu. "Material Balance Method and Dynamic Pressure Monitoring for Water-Bearing Gas Reservoirs with CO2 Injection". Energies 16, n. 12 (8 giugno 2023): 4592. http://dx.doi.org/10.3390/en16124592.

Testo completo

Abstract (sommario):

The storage of carbon dioxide by injecting carbon dioxide into gas reservoirs has become an important technique for achieving carbon capture, utilization, and storage. However, most studies have focused on tight gas reservoirs, and there are still few studies on the injection of carbon dioxide into water-bearing gas reservoirs. This paper analyzes the variation of reservoir pressure during CO2 injection and points out the optimal amount of CO2 injection in the reservoir, which can provide theoretical guidance in practical applications. The relationship is plotted between the formation pressure and the volume of injected carbon dioxide. The effects of reservoir inhomogeneity and the water content on the formation pressure are discussed. Dynamic monitoring of the formation pressure during carbon dioxide injection is achieved. The optimal volume of injected carbon dioxide for water-bearing gas reservoirs is determined. The results show that the formation pressure increases with an increase in the volume of injected carbon dioxide, and the curve exhibits a trend of steep increases at both ends and a gentle increase in the middle. Enhanced reservoir inhomogeneity and a low reservoir water content are favorable for carbon dioxide injection.

Gli stili APA, Harvard, Vancouver, ISO e altri

46

Candido, Kenneth D. "Concordant Pressure Paresthesia During Interlaminar Lumbar Epidural Steroid Injections Correlates with Pain Relief in Patients with Unilateral Radicular Pain". Pain Physician 5;16, n. 5;9 (14 settembre 2013): 497–511. http://dx.doi.org/10.36076/ppj.2013/16/497.

Testo completo

Abstract (sommario):

Background: Transforaminal and interlaminar epidural steroid injections are commonly used interventional pain management procedures in the treatment of radicular low back pain. Even though several studies have shown that transforaminal injections provide enhanced short-term outcomes in patients with radicular and low back pain, they have also been associated with a higher incidence of unintentional intravascular injection and often dire consequences than have interlaminar injections. Objectives: We compared 2 different approaches, midline and lateral parasagittal, of lumbar interlaminar epidural steroid injection (LESI) in patients with unilateral lumbosacral radiculopathic pain. We also tested the role of concordant pressure paresthesia occurring during LESI as a prognostic factor in determining the efficacy of LESI. Study Design: Prospective, randomized, blinded study. Setting: Pain management center, part of a teaching-community hospital in a major metropolitan US city. Methods: After Institutional Review Board approval, 106 patients undergoing LESI for radicular low back pain were randomly assigned to one of 2 groups (53 patients each) based on approach: midline interlaminar (MIL) and lateral parasagittal interlaminar (PIL). Patients were asked to grade any pressure paresthesia as occurring ipsilaterally or contralaterally to their “usual and customary pain,” or in a distribution atypical of their daily pain. Other variables such as: the Oswestry Disability Index questionnaire, pain scores at rest and during movement, use of pain medications, etc. were recorded 20 minutes before the procedure, and on days 1, 7, 14, 21, 28, 60, 120, 180 and 365 after the injection. Results: Results of this study showed statistically and clinically significant pain relief in patients undergoing LESI by both the MIL and PIL approaches. Patients receiving LESI using the lateral parasagittal approach had statistically and clinically longer pain relief then patients receiving LESI via a midline approach. They also had slightly better quality of life scores and improvement in everyday functionality; they also used less pain medications than patients receiving LESI using a midline approach. Furthermore, patients in the PIL group described significantly higher rates of concordant moderate-to-severe pressure paresthesia in the distributions of their “usual and customary pain” compared to the MIL group. In addition, patients who had concordant pressure paresthesia and no discordant pressure paresthesia (i.e., “opposite side or atypical”) during interventional treatment had better and longer pain relief after LESI. Two patients from each group required discectomy surgery in the one-year observation period. Limitations: The major limitation of this study is that we did not include a transforaminal epidural steroid injection group, since that is one of the approaches still commonly used in contemporary pain practices for the treatment of low back pain with unilateral radicular pain. Conclusions: This study showed that the lateral parasagittal interlaminar approach was more effective than the midline interlaminar approach in targeting low back pain with unilateral radicular pain secondary to degenerative lumbar disc disease. It also showed that pressure paresthesia occurring ipsilaterally during an LESI correlates with pain relief and may therefore be used as a prognostic factor. Key words: lumbar epidural steroid injection, interlaminar injection, low back pain, unilateral radicular pain, midline interlaminar approach, lateral parasagittal interlaminar approach, pressure paresthesia, quality of life, everyday functionality

Gli stili APA, Harvard, Vancouver, ISO e altri

47

Sardarian, M., O. Mirzaee e A. Habibolahzadeh. "Influence of injection temperature and pressure on the properties of alumina parts fabricated by low pressure injection molding (LPIM)". Ceramics International 43, n. 6 (aprile 2017): 4785–93. http://dx.doi.org/10.1016/j.ceramint.2016.11.208.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

48

Payri, Raul, Joaquin De la Morena, Vincenzo Pagano, Ali Hussain, Gilbert Sammut e Les Smith. "One-dimensional modeling of the interaction between close-coupled injection events for a ballistic solenoid injector". International Journal of Engine Research 20, n. 4 (13 marzo 2018): 452–69. http://dx.doi.org/10.1177/1468087418760973.

Testo completo

Abstract (sommario):

In this article, an investigation of a solenoid common-rail injector has been carried out to understand the hydraulic interactions between close-coupled injection events. For this purpose, a one-dimensional model of the injector was developed on GT-SUITE software. The geometrical and hydraulic characteristics of the internal elements of the injector, needed to construct the model, were obtained by means of different custom-made experimental tools. The dynamic behavior of the injector was characterized using an EVI rate of injection meter. The hydraulic results from the model show a good alignment with the experiments for single injections and a varied degree of success for multiple injections. Once the model was validated, it has been used to understand the injector performance under multiple-injection strategies. The mass of a second injection has shown to highly depend on the electrical dwell time, especially at low values, mostly due to the dynamic pressure behavior in the needle seat. The critical dwell time, defined as the minimum electrical dwell time needed to obtain two independent injection events, has been numerically obtained on a wide range of operating conditions and correlated to injection pressure and energizing time of the first injection. Finally, the increase in the needle opening velocity of the second injection compared to the single-injection case has been analyzed for close-coupled injection events.

Gli stili APA, Harvard, Vancouver, ISO e altri

49

Liu, Yiqiang, Yufei Meng, Qiyuan Liu, Huijun Zhang, Cheng Chen e Xiaonan Li. "Effect of multiple injection optimization on combustion characteristics of low-pressure EGR system engine". Journal of Physics: Conference Series 2805, n. 1 (1 agosto 2024): 012012. http://dx.doi.org/10.1088/1742-6596/2805/1/012012.

Testo completo

Abstract (sommario):

Abstract In recent years, reducing oil consumption and pollutant discharge in transportation industry has become an important measure to alleviate energy crisis and environmental pollution. Therefore, the fuel economy and emission characteristics of the engine have become an important index to evaluate the quality of an engine, so EGR technology has gradually become the standard of gasoline engines. But EGR is not always good. In order to alleviate the adverse effects of EGR on combustion, further research on engine combustion is needed. In order to study the effect of multiple injection strategy on engine combustion characteristics, this paper takes a high pressure direct injection gasoline engine equipped with low pressure EGR system as the research object, and verifies the designed multiple injection strategy on special test equipment. A large amount of combustion data of the engine under the same load, different fuel injection stages and fuel injection ratios were collected. By comparing the evaluation indexes of main pollutant emission, fuel consumption and combustion stability, it is found that with the increase of injection times, the combustion characteristics and knock of the engine show a trend of improvement. After using multiple injection strategies at 2000r/min, it can be seen that the optimized injection strategy has better emission characteristics and lower fuel consumption lower knock intensity than that before the injection mode optimization without affecting the power performance.

Gli stili APA, Harvard, Vancouver, ISO e altri

50

Xu, Wenjie, Xigui Zheng, Cancan Liu, Peng Li, Boyang Li, Kundai Michael Shayanowako, Jiyu Wang, Xiaowei Guo e Guowei Lai. "Numerical Simulation Study of High-Pressure Air Injection to Promote Gas Drainage". Sustainability 14, n. 21 (22 ottobre 2022): 13699. http://dx.doi.org/10.3390/su142113699.

Testo completo

Abstract (sommario):

Coal-accompanying gas is an essential resource, with numerous mining methods. The practice has proved that injecting high-pressure air into the coal seam can replace and flush the gas in the coal seam, effectively solving the problem of inadequate single gas drainage in soft and low permeability coal seams. This paper uses the finite element method to solve the model, simulate and study the gas drainage by high-pressure air injection in the bedding drilling, and establish a fluid-structure coupling model for gas drainage by high-pressure air injection. The competitive adsorption of N2, O2, and CH4, diffusion and migration of CH4 in coal matrix and fissure, matrix deformation caused by CH4 adsorption, and desorption and control of coal deformation by applied stress are considered in the model. When the fixed extraction time is 600 days (d), the optimal spacing between the extraction hole and injection hole is 12.5 m. The safe extraction effect and minimum drilling amount can be ensured. It provides a basis for guiding gas drainage by injecting high-pressure air on-site.

Gli stili APA, Harvard, Vancouver, ISO e altri

Articoli di riviste sul tema "Low-pressure injection"

Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili