Pressure Reduction Rate Research Articles

Effects of pressure depletion rate, solvent, and surfactant on non‐equilibrium reactions in foamy oil

AbstractThis research employed a visual method to explore the behaviour of foamy oil in heavy oil systems. A Hele‐Shaw cell was designed for observing the volumetric expansion of foamy oil as the system pressure decreased. This approach facilitated an examination of foamy oil's interface evolution under pressure depletion and an analysis of bubble sizes and their distribution. Using Minitab, 15 experiments were strategized, aimed at observing the distribution of bubbles and their stability during the foamy oil process. The investigation also extended to studying the influence of surfactants, solvent type, and pressure reduction rate on foamy oil. The findings suggest that a high concentration of surfactant, a high percentage of CO2 solvent, and a rapid pressure drop rate all contributed to the generation of microbubbles and enhanced volumetric expansion and stability of foamy oil. However, in light of the conducted energy analysis, a lower rate of pressure reduction is recommended. Finally, the conditions of the 15 experiments were applied to the CMG to derive two non‐equilibrium reactions for bubble generation and collapsing. The reaction rates are such that they relate bubble generation to the pressure reduction rate of the process and bubble resistance to collapsing to the surfactant concentration of the foamy oil.

Initial Clinical Experience with Ahmed Valve in Romania: Five-Year Patient Follow-Up and Outcomes.

Glaucoma is a leading cause of irreversible blindness worldwide and is particularly challenging to treat in its refractory forms. The Ahmed valve offers a potential solution for these difficult cases. This research aims to assess the initial clinical experience with Ahmed valve implantation in Romania, evaluating its effectiveness, associated complications, and overall patient outcomes over a five-year period. We conducted a prospective study on 50 patients who underwent Ahmed valve implantation due to various types of glaucoma. Patients were monitored at several intervals, up to five years post-surgery. Intraocular pressure and visual acuity were the primary measures of success. On average, patients maintained the intraocular pressure within the targeted range, with the mean intraocular pressure being 17 mmHg 5 years post-surgery. Success, defined as maintaining target intraocular pressure without additional surgery, was achieved in 82% at 1 year, 68% at 3 years, and 60% after 5 years postoperative. Ahmed valve implantation is a viable treatment option for refractory glaucoma, demonstrating significant intraocular pressure reduction and manageable complication rates over a five-year follow-up period. Future research should focus on long-term outcomes and optimization of surgical techniques to further reduce complication rates and improve patient quality of life.

Clinical Results of the MINIject Implant for Suprachoroidal Drainage.

Objective: This retrospective study evaluated the safety and efficacy of the new minimally invasive MINIject implant placed in the suprachoroidal space. The aim was to assess its impact on intraocular pressure (IOP) reduction and complication rate. Methods: 18 eyes from 18 patients with insufficiently controlled glaucoma received the implant using topical medications. Outcomes were changes in IOP, change in IOP medication, need for other glaucoma surgery, and rate of adverse events. Results: IOP reduced by 15% (p < 0.05) following MINIject implantation. IOP medication decreased from 3 to 1 agent (p < 0.05). Four patients (22%) required other glaucoma surgery while we did not observe any clinically relevant adverse event. Conclusions: This retrospective study indicates that MINIject implants may be a safe and effective means of reducing IOP together with a reduction in IOP medications in most patients. Larger prospective studies with longer follow-ups are necessary to confirm our results, though.

75. The Association of Intravenous Nitrates Dosing Regimens on Blood Pressure Reduction and ICU Admission Rates among Acute Hypertensive Heart Failure Patients in Emergency Settings: A Systematic Review, Meta Analysis, and Meta-Regression

75. The Association of Intravenous Nitrates Dosing Regimens on Blood Pressure Reduction and ICU Admission Rates among Acute Hypertensive Heart Failure Patients in Emergency Settings: A Systematic Review, Meta Analysis, and Meta-Regression

10. The Association of Intravenous Nitrates Dosing Regimens on Blood Pressure Reduction and ICU Admission Rates among Acute Hypertensive Heart Failure Patients in Emergency Settings: A Systematic Review, Meta Analysis, and Meta-Regression

10. The Association of Intravenous Nitrates Dosing Regimens on Blood Pressure Reduction and ICU Admission Rates among Acute Hypertensive Heart Failure Patients in Emergency Settings: A Systematic Review, Meta Analysis, and Meta-Regression

Efficacy and safety of first-line or second-line selective laser trabeculoplasty for normal-tension glaucoma: a multicentre cohort study

Background/aimsThis study aimed to investigate and compare the efficacy and safety of first-line and second-line selective laser trabeculoplasty (SLT) in Japanese patients with normal-tension glaucoma (NTG).Methods100 patients with NTG were...

An insight on reaction kinetics of amino-acid-functionalized ionic liquid monoethanolamine glycinate for CO2 capture

ABSTRACT Recently, the application of functionalized ionic liquids in carbon dioxide (CO2) capture has received significant attention. In this research, the absorption kinetics of CO2 into the aqueous amino-acid-functionalized monoethanolamine glycinate ionic liquid in a stirred cell reactor was investigated. Amino acids are less volatile and have good resistance against oxidative degradation. Experiments were accomplished over a temperature range of 298–308 K and solution concentrations ranging from 0.5 to 2.5 M in the pseudo-first-order regime. The dimensionless Hatta number and infinite enhancement factor were calculated to check the fast pseudo-first-order reaction assumption. The reaction rate constant has been evaluated by recording the system pressure reduction rate over time. Increasing the IL concentration and temperature results in a significant increase in the reaction rate. The obtained kinetic constants have the same order of magnitude as those existing for primary amines.

Investigation of a new reverse drainage construction and the pressure-reducing effect of a tunnel in a water-rich karst location

It is quite simple to create cracking, leaking, and other disasters in the tunnel during operation because water-rich karst tunnels are subject to the action of the high head. If the drainage is not timely, this results in high-pressure water collection around the tunnel lining. The study was conducted depending on Tongzi Tunnel to resolve the issue of water pressure encountered by water-rich karst tunnel lining under high head action and to lessen the issue of operational tunnel illness under long-term water pressure. The mechanical reaction of the number of reverse drainage holes and the size of pipe diameter at the raised arch under various water heads on the tunnel construction was studied using model testing in combination with numerical simulation analysis. It was discovered that using the traditional drainage system would subject the supine arch to extremely high-water pressure, which is often hard to efficiently remove. The major issue causing the elevated arch bulging tragedy is that water pressure in the elevated arch increases as head height increases. High water pressure in the raised arch may be efficiently dealt with using the suggested reverse drainage approach. The pressure reduction rate compared to the traditional drainage method achieved 13.6 % for the investigation of the fractured Tongzi tunnel reverse drainage holes, which had a total of five holes with a diameter of roughly 100 mm. Reverse drainage structures have the potential to save project costs while also realizing “point to point” pressure reduction at the elevation arch of the tunnel and have positive effects on total tunnel pressure reduction. The study's findings can serve as a guide for designing and building comparable water-rich karst tunnel constructions as well as for maintaining drainage systems while they are in use.

Comparison of the efficacy of micropulse diode laser transscleral cyclophotocoagulation using different energy protocols.

This study aimed to explore the safety and efficacy of laser treatment settings of micropulse transscleral cyclophotocoagulation treatment in glaucoma patients and to evaluate the relationship between intraocular pressure (IOP) reduction and different treatment parameters. A total of 74 eyes in 64 glaucoma patients with IOP over 21 mmHg or under 20 mmHg with visual field progression who underwent micropulse transscleral cyclophotocoagulation treatment were included. Patients were divided into success and failure groups based on criteria of 20% IOP reduction rate. The predictive factors of IOP reduction between success and failure groups and the IOP reduction rates in the different treatment duration groups were evaluated. Predictive factors for IOP reduction were analyzed using univariate and multivariate regression models. Patients in the success group had significantly higher baseline IOP (median: 28.0 vs. 23.0 mmHg; P = 0.016) and longer treatment times (median: 240 vs. 160 s; P = 0.001). Treatment duration range between 200 and 240 s achieved significantly higher intraocular pressure reduction rates (47.8 ± 17.4%) than durations under 140 s (23.1 ± 14.2%). Univariate analysis showed that baseline IOP and treatment duration were significant contributing factors in IOP reduction. Multivariable analysis further demonstrated that treatment duration over 200 s was the significant predictive factor for IOP reduction. Treatment duration settings were the most significant factor of IOP reduction rates in micropulse cyclophotocoagulation. Customized therapy according to the target IOP reduction rate can be applied with different treatment duration settings to achieve optimal outcomes.

TEN-YEAR OUTCOMES OF TIPS FOR BUDD-CHIARI SYNDROME: SYSTEMATIC REVIEW AND META-ANALYSIS.

Budd-Chiari syndrome (BCS) results from the obstruction of the hepatic venous flow, usually at the level of the hepatic vein or inferior vena cava. When left untreated, it can progress with several complications, including liver cirrhosis. Transjugular intrahepatic portosystemic shunt (TIPS) appears to be effective in a subgroup of BCS patients. To perform a systematic review and meta-analysis of TIPS effectiveness in BCS treatment, considering the survival rate, reduction in portosystemic pressure, need for liver transplantation, technical failure, and shunt dysfunction for up to 10 years of follow-up. We evaluated 17 studies published in PubMed, Science Direct, Web of Science, and SCOPUS databases, which used TIPS as a treatment for BCS, comprising 618 subjects between 18 and 78 years old. We assessed the bias risk by the NOS, NHI, and JBI scales for cohort stu-dies, before-after studies, and case series, respectively. We conducted the meta-analyses by extracting the number of events and the total patients evaluated to perform the proportion meta-analyses using the R software ("meta" package - version 4.9-6). The pooled results (95%CI) showed a 19% (25.9-12.5%) rate of portosystemic pressure reduction, 6% (1-12%) rate for the need for liver transplants despite the use of TIPS, 2% (1-6%) technical failure rate, 30% (18-46%) shunt dysfunction rate, and 88% (81-93%) for the mean frequency of patients alive between 1 and 10 years after the procedure. We stratified survival rate and found an 86% (74-93%) prevalence of living subjects during less than five years, 92% (83-97%) at five years, and a 77% frequency (68-83%) of patients alive ten years after the TIPS placement. TIPS is an effective treatment for BCS, providing a high 10-year frequency of living patients and a significant decrease in portosystemic pressure. The need for liver transplants after TIPS and the technical failure rate is low.

A meta‐analysis of surgical treatments for childhood glaucoma

Aims/Purpose: To assess the comparative efficacies of surgical interventions for childhood glaucoma (CG).Methods: Through electronic database searches up to August 7, 2022, randomized controlled trials (RCTs) involving surgical interventions for CG were identified. A meta‐analysis was conducted to compare the surgical interventions: Conventional partial trabeculotomy ([CPT] control), 240‐degree trabeculotomy, Illuminated microcatheter‐assisted circumferential trabeculotomy (IMCT), Viscocanalostomy, Visco‐circumferential‐suture‐trabeculotomy, Goniotomy, Laser goniotomy, Kahook dual blade ab‐interno trabeculectomy, Trabeculectomy with mitomycin C, Trabeculectomy with modified scleral bed, Deep sclerectomy, Combined trabeculectomy‐trabeculotomy with mitomycin C, and Baerveldt implant. The main outcome measures were postoperative 6‐month mean intraocular pressure (IOP) reduction and surgical success rate. The mean differences (MDs) or odds ratios (ORs) were obtained using a random‐effects model, and the efficacies were ranked by P‐score.Results: Sixteen (16) RCTs were eligible for inclusion in the analysis, involving 710 eyes of 485 participants and 13 surgical interventions, which formed a 14‐node network. IMCT was superior to CPT in both IOP reduction (MD [95% CI], −3.10 [−5.50 to −0.69]) and surgical success rate (OR [95% CI], 4.38 [1.61 to 11.96]), while the MD and OR comparing the other surgical interventions with CPT were not statistically significant. Moreover, the IMCT was ranked as the most efficacious surgical intervention for success rate (P‐score = 0.777).Conclusions: This meta‐analysis revealed that IMCT is more effective than CPT and might be the most efficacious surgical intervention for CG.

Investigation on absorption separation characteristics of R134a, R1234yf, R22, R410A, and R404A using MWCNT-[HMIM][Tf2N] ionanofluid

In this study, refrigerant absorption characteristics of R134a, R1234yf, R22, R410A, and R404A were investigated using MWCNT-[HMIM][Tf2N] ionanofluid (IONF) for environmental improvement towards a sustainable future. During the absorption experiment, the remaining free volume space was reduced when the refrigerant was recharged in Cycle-2, and the average pressure reduction rate in Cycle-1 was increased by 18.2 % compared to Cycle-2. In addition, the solubility between the refrigerant and IONF had a more significant influence on the absorption performance than the concentration. The relative refrigerant absorption performance for the separation of mixed refrigerants increased by interfering with the absorption of refrigerants with relatively large molecular sizes as the concentration of IONF increased. Compared to 0 wt%, the relative absorption performance at 0.5 wt% concentration of MWCNT-[HMIM][Tf2N] IONF increased by 123.9 %, 26.4 %, and 123.9 %, respectively, for R22/R134a, R22/R1234yf, and R134a/R1234yf. It was confirmed that the refrigerant recovery and waste refrigerant treatment using MWCNT-[HMIM][Tf2N] IONF have sufficient potential to reduce environmental degradation and considered to be aneconomically viable method.

Efficacy of acupuncture for hypertension in the elderly: a systematic review and meta-analysis.

Hypertension has now developed into a major public health problem worldwide. Under the existing antihypertensive drug treatment paradigm, problems such as decreasing drug resistance and increasing drug side effects can occur for elderly patients. Acupuncture, a core technique in the non-pharmacological treatment of Chinese medicine, plays an important role in the treatment of elevated blood pressure. This study aimed to systematically evaluate the effect of acupuncture alone or in combination with antihypertensive drugs on the efficiency of reducing blood pressure and controlling blood pressure in elderly patients with hypertension. Articles of randomized controlled trials of acupuncture for hypertension in the elderly published before November 2022 were searched in 7 databases. The methodological quality of the literature was evaluated using the Cochrane Risk of Bias Assessment Tool. The primary outcome was the efficiency rate of blood pressure reduction, and the secondary outcome was the change in blood pressure after treatment. This study conducted a systematic review and meta-analysis of 12 randomized controlled trials with a total of 1,466 subjects. Among the primary outcome-efficiency rate, acupuncture-only treatment (RR = 1.11, 95% CI: 1.03-1.20, P < 0.01) and acupuncture combined with antihypertensive drug treatment (RR = 1.18, 95% CI: 1.06-1.31, P < 0.01) were significantly different compared with drugs-only treatment. Among the secondary outcomes, SBP (MD: -4.85, 95% CI: -10.39 to -0.69, P = 0.09) and DBP (MD: -1.45, 95% CI: -5.35 to 2.45, P = 0.47) show no significant difference between acupuncture-only treatment and drug-only treatment. Compared to drugs-only treatment, acupuncture plus drugs has more significant efficiency in lowering SBP (MD: -9.81, 95% CI: -13.56 to -6.06, P < 0.01) and DBP (MD: -7.04, 95% CI: -10.83 to -3.24, P < 0.01). For elderly patients with hypertension, acupuncture-only treatment has the same efficiency and antihypertensive effect compared to drug therapy and acupuncture plus drugs outperforms drugs-only treatment. If the patients receive therapy with less frequency per week and longer duration, there will be a more obvious antihypertensive effect. Due to the methodological defects in the included study and the limited sample size of this paper, more well-designed randomized controlled trials are needed for verification. https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022376407, PROSPERO (CRD42022376407).

Experimental study of the influencing factors and mechanisms of the pressure-reduction and augmented injection effect by nanoparticles in ultra-low permeability reservoirs

Nanoparticles (NPs) have gained significant attention as a functional material due to their ability to effectively enhance pressure reduction in injection processes in ultra-low permeability reservoirs. NPs are typically studied in controlled laboratory conditions, and their behavior in real-world, complex environments such as ultra-low permeability reservoirs, is not well understood due to the limited scope of their applications. This study investigates the efficacy and underlying mechanisms of NPs in decreasing injection pressure under various injection conditions (25–85 °C, 10–25 MPa). The results reveal that under optimal injection conditions, NPs effectively reduce injection pressure by a maximum of 22.77% in core experiment. The pressure reduction rate is found to be positively correlated with oil saturation and permeability, and negatively correlated with temperature and salinity. Furthermore, particle image velocimetry (PIV) experiments (25 °C, atmospheric pressure) indicate that the pressure reduction is achieved by NPs through the reduction of wall shear resistance and wettability change. This work has important implications for the design of water injection strategies in ultra-low permeability reservoirs.

Evaluation of the Effects of Nano-SiO2 Microemulsion on Decompression and Augmented Injection in the Eunan Tight Reservoir

The residual oil saturation of the matrix near the well zone of a tight reservoir is high due to the tight reservoir’s complex conditions, such as the small pore throat radius and low permeability of the matrix and the development of microfractures, which can result in serious water channeling, even after long-term water injection development. The aim of this paper is to improve the effects of depressurization and augmented injection for tight reservoir waterflooding development by reducing the tight matrix’s residual oil saturation, increasing and maintaining its water phase permeability near the well zone using a nano-SiO2 microemulsion system with a small particle size and high interfacial activity. Therefore, four nano-microemulsion systems were evaluated and screened for their temperature resistance, salt resistance, interfacial tension, solubilization, and dilution resistance. A microemulsion system of 13% A + 4% B + 4% C + 4% n-butanol + 6% oil phase + 69% NaCl solution (10%) + 1% OP-5 + 0.5% anti-temperature agent + 0.3% nanosilica material was preferred. According to the core displacement experiment, the depressurization rate can reach 28~60% when the injection concentration of the system is 1~10% and the injection volume is 2~5 PV. The results of the on-site test show that the water injection pressure dropped to 17.5 MPa, which was lower than the reservoir fracture re-opening pressure. The pressure reduction rate was approximately 20%. The validity period of the depressurization and augmented injection has reached 23 months to date.

Carbon dots nanofluid: Reducing injection pressure in unconventional reservoir by regulating oil/water/rock interfacial properties

Effective development of unconventional resources is impeded by water flooding-related challenges, such as high pressure and under-injection, which hinder the replenishment of formation energy. Nanofluids have shown promise in reducing injection pressure, but traditional nanoparticles (NPs) face limitations in unconventional reservoirs due to their unsuitable size for micro-nano pores and aggregation tendencies. In this paper, novel carbon dots (CDs) with a simple, environmentally benign, and controllable synthetic approach have been developed, and their pressure-reduction performance and mechanism have been systematically explored. The particle size of the CDs could be tailored by a well-timely quenching reaction. CDs nanofluid demonstrated superior stability, dispersibility, and temperature/salinity resistance. In addition, CDs can regulate interfacial properties, including oil/rock and oil/water interfaces. It was found that CDs could be partially absorbed onto pore walls, reducing oil adhesion sites by 39%, altering wettability from oil-wet to neutral, and reducing rock surface roughness by 29.25%. Furthermore, CDs were rapidly adsorbed onto the remaining oil film in the pore space, reducing interfacial tension while solidifying the oil surfaces, increasing shear force around the oil surface by 1.7 times during subsequent water scouring, which makes the oil film break up more readily and remain smaller in size to migrate in the channeling. The modulation of the interface properties by CDs improved the stripping efficiency of the attached oil film and ameliorated the homogeneity and smoothness of flow channel, resulting in a significant reduction in injection pressure. Core displacement tests showed that a 0.1 wt% CDs nanofluid could achieve a pressure reduction rate of 35%. The developed CDs nanofluid represents a promising solution for reducing injection pressure and improving oil recovery in unconventional reservoirs.

Experimental research on combustible gas/air explosion inhibition by dry water

The carbon reduction policy to address environmental change has increased the storage, transportation, and use of clean energy represented by hydrogen (H2) and natural gas (mainly composed of methane, CH4). However, its risk of ignition and explosion also brought significant safety risks. Although many previous studies have studied the effect of traditional detonation inhibitors, the inhibition effect of composite explosion inhibition materials still needs further research, especially for H2 explosion inhibition. In this paper, the effect of dry water (DW), a new type of core-shell structure material, in inhibiting the explosion of combustible gases (mainly H2 and CH4) has been experimentally studied using a typical 20L spherical apparatus. The results shows that DW can significantly reduce the characteristic parameters during the ignition and explosion process of H2 and CH4. However, its ignition and explosion inhibition effect is related to the type of combustible gas. The maximum explosion pressure of CH4 is significantly reduced, but the maximum pressure reduction rate of H2 is more significantly reduced. Compared with typical dry powder inhibitors, the effect of DW inhibition in characteristic parameters during the H2 ignition and explosion is related to concentration. Moreover, the inhibition effect of DW at higher concentrations is significantly better than BC and ABC dry powders at the same concentration. The inhibition mechanism of DW on the ignition and explosion of combustible gases results from a comprehensive synergy of cooling, dilution, homogeneous radical catalytic inhibition, and heterogeneous radical annihilation. The research conclusions can provide a data basis and theoretical guidance for developing explosion inhibition technology and preventing and controlling H2 explosions.

Numerical Simulation of Superheated Steam Flow and Heat Transfer in a Balanced Steam Injection Flow Control Device

Dual-string steam injection pipe is widely used in the production of superheated steam injection in heavy oil horizontal wells. Due to the nonuniform steam injection volume at the heel end and the existence of an interlayer and other factors in the reservoir, the distribution of steam cavity is not uniform, so it is necessary to control the flow of the steam injection well. Based on the basic principles of fluid mechanics and heat transfer, a three-phase nozzle outflow control device model is established in this paper. The steam flow and heat transfer law in the flow control device is numerically simulated, and the outflow dynamic law of horizontal well OCD completion in heavy oil reservoir is obtained. On this basis, the influence of OCD aperture parameters, steam injection pressure, and steam injection velocity on OCD throttling effect is studied. The results show that OCD has a good control effect on balancing pressure drop and improving steam injection uniformity. When the throttle aperture occupies 1/3 of the pipe diameter, the throttle effect is the best and the heat loss is low. Increasing the steam injection pressure can rapidly enhance the pressure reduction rate of the throttle hole. The throttling effect of increasing steam injection volume is not obvious, and the energy loss becomes higher. The study of this paper provides a reference for parameter optimization and prediction of steam distribution in the flow control device of horizontal wells.

Investigation of the Damage Phenomenology with Dependence on the Macroporosity and Microporosity of Porous Freeze Foams

Freeze Foams are cellular, ceramic structures with hierarchical pore structures that are manufactured using the direct foaming process. By tailoring their morphology and strength, these foam structures are able to cover a wide range of application. Earlier works identified that pore-forming influencing factors (water and air content, suspension temperature, as well as pressure reduction rate) dictate the constitution on a macroscopic and microscopic scale. Therefore, the ability to manufacture foams whose properties align with the component requirements would be an important step in advancing towards a widespread application of these promising materials. With this goal in mind, the correlation between the pore-forming influencing factors and the resulting mechanical properties was quantified. Foams with independently adjustable porosities were produced at the micro and macro scales and evaluated according to their material failure behavior under compressive loads. As a result, foams with determined macroporosities between 38 and 62%, microporosities between 25 and 42%, and compression strengths between 1 and 7 MPa with different material failure characteristics were manufactured and systematically investigated.

Research on the Effect of the Outlet Throttle Diameter Deviation on the Pressure Relief Rate of the Injector Control Valve

Common rail injector response characteristics depend on the control chamber pressure change rate, the outlet throttle diameter by manufacturing errors, or wear-induced deviations that affect the rate of pressure change in the control chamber, so the accuracy of the outlet throttle diameter directly affects the control valve response consistency. This paper presents a computational fluid dynamics (CFD) simulation of the effect of the deviation of the outlet throttle diameter on the average mass flow rate of the outlet throttle during the opening of the spherical valve in order to reduce this difference and ensure uniform injection characteristics. The results illustrate that with the increase in outlet throttle diameter deviation, the volume of gas phase in the control valve increases and the rate of pressure reduction in the control chamber accelerates, and the sensitivity coefficient of the average mass flow rate of the outlet throttle to the outlet throttle diameter deviation remains unchanged at 24.77. Cavitation occurs in the area of the outlet throttle when the spherical valve lift is 0.045 mm. The increase in rail pressure not only leads to an increase in the low-pressure area on the inner wall of the outlet throttle, an increase in the volume share of the gas phase, and an increase in the hydraulic impact on the sealing wall but also makes the average mass flow rate of the outlet throttle and the rate of change of the control chamber pressure during the opening of the spherical valve more sensitive to the deviation of the outlet throttle diameter.