Pressure Difference Research Articles

Design and systematic evaluation of an under-canopy robotic spray system for row crops

Despite having made much improvement in sensing, automation, and control, the current broadcast spraying system has several drawbacks, such as uneven coverage, excessive chemical use, and deviation from recommended dosage. Typically, farmers use large self-propelled sprayers to spray the entire field without knowledge of spatial pest severity, potentially resulting in an unintentional application. However, application errors and the extent of chemical use can be optimized by utilizing an intelligent site-specific decision-based sprayer to control pests more efficiently. Hence, the initial project goal was to design a robotic liquid application system for row crops (e.g., sorghum and corn) and validate sprayer system performance. The critical design considerations for the spray application system were modularity; the ability to be mounted on an autonomous platform to go within 76.2-cm spaced crops; spray on either side of the crop row using spray booms; onboard hardware and software for control and data acquisition; and record as-applied data. A system with desired design requirements was built and individual sub-systems were tested under simulated lab scenarios to quantify the response time and accuracy of the spray system. The results showed that the sprayer could maintain an average system pressure within ±5% of the target under different duty cycles for each of the six nozzles. At 40% duty cycle, the nozzle pressure settling time at an error margin of ±5% from the mean was 13 ms, 20 ms, and 19 ms, for one, three, and six nozzles, respectively. Also, no substantial pressure difference was observed between nozzles installed at different heights in two different booms. Therefore, this application system could be a viable solution for autonomous platforms to site-specifically apply pesticides only on critically infested plants, has the potential to decrease the overall input costs on chemicals and reduce the negative environmental impacts.

Assessment of Left Ventricular Diastolic Function in Patients with Diffuse Large B-cell Lymphoma after Anthracycline Chemotherapy by using Vector Flow Mapping.

Patients with diffuse large B-cell lymphoma (DLBCL) often experience a poor prognosis due to cardiac damage induced by anthracycline chemotherapy, with left ventricular diastolic dysfunction manifesting early. Vector Flow Mapping (VFM) is a novel technology, and its effectiveness in detecting left ventricular diastolic dysfunction following anthracycline chemotherapy remains unverified. This study evaluates left ventricular diastolic function in DLBCL patients after anthracycline chemotherapy using vector flow mapping (VFM). We prospectively enrolled 54 DLBCL patients who had undergone anthracycline chemotherapy (receiving a minimum of 4 cycles) as the case group and 54 age- and sex-matched individuals as controls. VFM assessments were conducted in the case group pre-chemotherapy (T0), post-4 chemotherapy cycles (T4), and in the control group. Measurements included basal, middle, and apical segment energy loss (ELb, ELm, ELa) and intraventricular pressure differences (IVPDb, IVPDm, IVPDa) across four diastolic phases: isovolumic relaxation (D1), rapid filling (D2), slow filling (D3), and atrial contraction (D4). When comparing parameters between the control and case groups at T0, no significant differences were observed in general data, conventional ultrasound parameters, and VFM parameters (all P > 0.05). From T0 to T4, ELa significantly increased throughout the diastole cycle (all P < 0.05); ELm increased only during D4 (all P < 0.05); and ELb increased during D1, D2, and D4 (all P < 0.05). All IVPD measurements (IVPDa, IVPDm, IVPDb) increased during D1 and D4 (all P < 0.05) but decreased during D2 and D3 (all P < 0.05). Significant positive correlations were identified between ELa-D4, IVPDa-D4, and parameters A, e', E/e,' and LAVI (all r > 0.5, all P < 0.001). Negative correlations were noted with E/A for ELa- D4 IVPDa-D4 (all r < -0.5, all P < 0.001). Positive correlations were observed for IVPDa-D1, IVPDa-D2 with E, E/e', and LAVI (0.3<r<0.5, all P<0.001). VFM parameters demonstrate a certain correlation with conventional diastolic function parameters and show promise in assessing left ventricular diastolic function. Furthermore, VFM parameters exhibit greater sensitivity to early diastolic function changes, suggesting that VFM could be a novel method for evaluating differences in left ventricular diastolic function in DLBCL patients before and after chemotherapy.

Experimental study on the influence of the riser on the gas-liquid flow in the horizontal pipeline of the offshore pipeline-riser system

The study of gas-liquid interface evolution and pressure fluctuation mechanism in the pipeline-riser system is the key to ensuring the safety of oil and gas transportation. This paper investigates the influence of the riser on the gas-liquid interface in the system with a 1657 m pipeline and risers of 16 m, 22 m, and 29 m. In severe slugging, the differential pressure in the horizontal pipeline exhibits a low-frequency large-amplitude fluctuation consistent with those in the riser. During the gas blowdown of the riser, the pressure fluctuation breaks the force equilibrium of the gas-liquid interface and induces numerous liquid slugs in the horizontal pipeline. A strong correlation is found between the differential pressure in the riser and the slug velocity in the horizontal pipeline by the Spearman Rank coefficient. The correlations between the slug velocity and the gas volume fraction and the void fraction under different riser heights are established, and the errors are 15% and 10%, respectively. The linear relationship between the Strouhal number of liquid slugs and the Lockhart-Martinelli parameter is constructed during the gas blowdown.

Effects of the nozzle design parameters on turbulent jet development of active pre-chamber

Active pre-chamber turbulent jet ignition is one of the most promising technologies for developing low- or zero-carbon engines. However, the relevant fundamental studies are far from adequate, particularly for the independent impact of the pre-chamber design parameters on the jet characteristics in the absence of combustion in the main chamber. In this study, the hot turbulent jet characteristics of the pre-chamber fueled with the premixed CH4-air are studied by the double-pass Schlieren imaging. The effects of the pre-chamber nozzle design parameters, including the orifice diameter, total orifice cross-sectional area, and orientation are clarified. The results reveal that the pressure difference between the pre-chamber and main chamber depends on the total orifice cross-sectional area. The effects of the orifice diameter and total orifice cross-sectional area on the penetration rate exhibit a trade-off relation, while the orifice diameter has a more pronounced effect on the hot jet projection area than the total orifice cross-sectional area. Compared to the inclined orifice, the penetration velocity of the straight orifice is faster at the initial hot jet ejection stage. These results are expected to be valuable references for the pre-chamber design and understanding of the ignition mechanisms of active pre-chamber.

Home blood pressure-lowering effect of a non-steroidal mineralocorticoid receptor blocker, esaxerenone, versus trichlormethiazide for uncontrolled hypertension: the EXCITE-HT randomized controlled study.

The EXCITE-HT study aimed to evaluate the efficacy and safety of esaxerenone versus thiazide diuretics (trichlormethiazide) as second-line treatment for Japanese patients with uncontrolled essential hypertension. This was a 12-week, multicenter, randomized, open-label, parallel-group study. The non-inferiority of esaxerenone to trichlormethiazide was confirmed if the upper limit of the two-sided 95% confidence interval (CI) for the difference in systolic blood pressure (SBP)/diastolic blood pressure (DBP) change between groups was below 3.9/2.1 mmHg. A total of 295 and 290 patients were included in the esaxerenone and trichlormethiazide groups, respectively. The non-inferiority of esaxerenone to trichlormethiazide was demonstrated: least squares mean change differences in morning home SBP/DBP at end of treatment (EOT) were -2.2 (95% CI, -3.6, -0.8) mmHg for SBP/-0.6 (-1.4, 0.2) mmHg for DBP. Morning home, bedtime home, and office BP significantly decreased (all p < 0.001) from baseline to EOT in both groups. The urinary albumin-to-creatinine ratio and N-terminal pro-brain natriuretic peptide level decreased from baseline to Week 12 in both groups, with no notable intergroup difference. Serum potassium elevations occurred more frequently with esaxerenone, while serum potassium reductions occurred more with trichlormethiazide. Uric acid elevations were observed in both groups, but more frequently with trichlormethiazide than esaxerenone. No cases of gout occurred in this study. Reductions in estimated glomerular filtration rate were similarly observed in both groups. EXCITE-HT is the first randomized controlled study to demonstrate evidence that esaxerenone is non-inferior to trichlormethiazide as second-line treatment for Japanese patients with uncontrolled essential hypertension, with no new safety concerns. The EXCITE-HT study demonstrated the non-inferiority of esaxerenone to trichlormethiazide in its morning home blood pressure lowering effect and safety profile in Japanese patients with uncontrolled essential hypertension who were previously treated with an angiotensin II receptor blocker or calcium channel blocker.

Projecting the long‐term effects of large‐scale human influence on the spatial and functional persistence of extant longleaf pine ecosystems in the Florida Flatwoods Pyrome

AbstractDecades of human activities and fire suppression have adversely affected longleaf pine (Pinus palustris) ecosystems, which are home to high levels of diversity and endemism. These iconic ecosystems also now face challenges from urbanization and climate change, which will alter conservation outcomes over the remainder of the 21st century. To explore how long‐term, large‐scale human influences could affect the spatial and functional persistence of extant longleaf pine ecosystems in the Florida Flatwoods Pyrome, we extracted a set of 2400 longleaf pine patches ≥40 ha in size from the Florida Longleaf Pine Ecosystem Geodatabase. Projections from the FUTURES urban growth model and the Florida 2070 project indicate that development will lead to losses of existing longleaf pine habitat, reductions in longleaf pine patch size, and patches that are predominantly located in close proximity to developed areas. Finer‐scale patterns of longleaf pine loss in three focal landscapes highlighted differences in land protection, ecological setting, and development pressure and the value of using of multiple urbanization iterations. The occurrence of suitable conditions to conduct prescribed fires, a crucial tool for maintaining, improving, and restoring longleaf pine ecosystems, is projected to decrease seasonally throughout the study area. As a result, the functional persistence of ecosystems is at risk due to climate changes that increase barriers to the safe and reliable application of intentional fire. The long‐term viability of this critical ecosystem will warrant the evaluation of adaptive strategies that explicitly account for the individual and compounding effects of urban development and changing fire management conditions when considering options for ecosystem protection, management, and restoration.

Moist air permeability characteristics of flexible contact gaskets used in refrigerators

Flexible contact gasket is a significant component affecting the sealing performance of the refrigerator. However, few studies were conducted on the permeability characteristics of moist air through refrigerator gaskets. The purpose of this study is to explore the permeability characteristics including permeation paths size, flow type, modeling and temperature-humidity-pressure-structure effect. The characteristic scale of the interface of permeation paths is observed as 10−5 m in the free-state by atomic force microscope. The equation of Knudsen number and contact stress relation is established to judgment the flow types. By comparing the critical and simulated contact stresses, it is inferred that moist air simultaneously occurs slip, transition and free-molecular flows. A multi-scale coupling model of permeation rate is constructed to obtain the apparent permeability coefficient characterizing the permeability intensity. The air pressure difference affects the permeability characteristics in the form of direct driving force and changing the contact stress of the interfaces. Free-molecular flow mainly occurs under the negative pressure condition with inhalation coefficient of 2.26 × 10−5∼2.84 × 10−5 m2, while the slip flow mainly occurs under the positive pressure conditions with exhalation coefficient of 2.87 × 10−5∼4.65 × 10−5 m2. The essence of enhancing the sealing performance of structural improvement is to increase the contact stress and length of permeation path. By increasing the height, increasing the inclination angle, adding the auxiliary edges and adding an auxiliary airbag, the inhalation coefficient of moist air, the exhalation coefficient of moist air and the inhalation coefficient of water vapor are decreased by 54.82 %, 51.46 % and 66.04 %.

Permeability Evolution of Shale during High-Ionic-Strength Water Sequential Imbibition

It is widely accepted in the oil and gas industry that high-ionic-strength water (HISW) can improve oil and gas recovery in unconventional shale reservoirs by limiting shale hydration. Despite numerous supporting studies, there is a lack of a systematic analysis exploring the effect of HISW on shale permeability evolution, particularly considering varying chemical compositions. In this work, we investigated the impact of different concentrations of NaCl and CaCl2 on shale permeability through sequential HISW imbibition experiments, beginning with the highest NaCl and lowest CaCl2 concentrations. After maintaining the highest effective stress for an extended period, significant permeability reduction and potential fracture generation were observed, as indicated by periodic fluctuations in differential pressure. These effects were further intensified by displacements with HISW solutions. Advanced post-experimental analyses using micro-CT scans and SEM-EDS analysis revealed microstructural changes within the sample. Our findings offer initial insight into how HISW-shale interactions influence shale permeability, using innovative approaches to simulate reservoir conditions. The findings indicate that discrepancies in the chemical composition between injected solutions and shale may lead to shale disintegration during hydraulic fracturing processes.

Measurement of air-water counter-current flow rates in vertical annulus using multiple differential pressure signals and machine learning

Abstract Gas–liquid counter-current flow in vertical annulus is involved in several industrial fields such as petroleum engineering. For example, in coalbed methane wells with liquid pump drainage, obtaining the real-time flow rate of gas–liquid two-phase in the annulus is crucial for the development management of coalbed methane wells. However, due to complex flow conditions, this demand is difficult to achieve through traditional flow metering means. Therefore, this paper proposes a flow prediction method based on multi-group differential pressure signals and machine learning technology. Air-water two-phase flow experiments were carried out on a vertical annulus pipeline with inner and outer diameters of 75 mm/125 mm and adjustable eccentricity. The probability density function and power spectrum density of 3 groups of differential pressure signals collected at different height intervals in the annulus were used as model inputs. A gas–liquid two-phase flow prediction model was constructed based on the artificial neural network model, and the model hyper-parameters were optimized using Bayesian optimization. The results show that on the 440-group test dataset under the combined conditions of air superficial velocity of 0.06–5.04 m s−1, water superficial velocity of 0.03–0.25 m s−1, and pipeline eccentricity of 0, 0.25, 0.5, 0.75, 1, etc. This model can achieve average prediction errors of 9.12% and 29.34% for gas and water flow rates respectively. This method can be applied to the non-throttling, non-invasive measurement of phase flow rate under the condition of annulus air-liquid counter-current flow.

Calibration of flow differential pressure coefficients on pump-turbine by thermodynamic method

On-line monitoring of flow rate is rather important to evaluate the water consumption of the pump-turbine and the overall efficiency of the pumped storage station. Flow rate can be worked out based on the flow differential pressure measured in the flow passage and coefficients determined on model test. But the coefficients must be calibrated to obtain the reliable flow rate. As thermodynamic method is a common way to measure the discharge of prototype pump-turbine, site test is carried out on a vertical pump-turbine with 600 m rated head to calibrated the coefficients in this paper. Measuring devices are designed to satisfy both the turbine and pump operating conditions, and test results of flow rate at both turbine and pump operating conditions are presented and show that the calibrated coefficients are different to the predicted values. The calibrated results indicate the importance of site calibration on prototype turbine to ensure the monitoring validity on real-time flow rate.

Self-Driven Gas Spreading on Mesh Surfaces for Regeneration of Underwater Superhydrophobicity.

Underwater superhydrophobic surfaces stand as a promising frontier in technological applications such as drag reduction, antifouling, and anticorrosion. Unfortunately, the air film, known as the plastron, on these surfaces tends to be unstable. To address this problem, active approaches have been designed to preserve or restore plastrons. In this work, a self-driven gas spreading superhydrophobic mesh (SHM) surface is designed to facilitate recovery of the plastron. The immersed SHM can be "wetted" by gas, even when the plastron is removed. We demonstrate that the injected gas can spread spontaneously along the SHM over a large area, which greatly simplifies the plastron replenishment process. By incorporating a locally coated gas-producing layer, we achieve rapid in situ plastron recovery and long-term immersion stability, extending the plastron lifespan by at least 48 times. We also provide a framework for designing an SHM with suitable structural dimensions for gas spreading. Furthermore, an SHM with asymmetric structural dimensions enables unidirectional gas transport by the capillary pressure difference. This SHM surface shows excellent drag reduction properties (37.2%) and has a high slip recovery coefficient (73.4%) after plastron loss. This facile and scalable method is expected to broaden the range of potential applications involving nonwetting-related fields.

Revisiting zircon Eu anomaly as a proxy for crustal thickness: A case study of the Sierra Nevada Batholith

We analyzed detrital zircon from the Sierra Nevada Batholith, western USA, to reassess whether zircon Eu/Eu* can be used to reconstruct crustal thickness in the past. Our reconstruction shows two episodes of crustal thickening between 80–200 Ma in the Sierra Nevada region—one during the Jurassic (170—140 Ma) and the other in the Cretaceous (110—80 Ma). These findings are consistent with the results obtained using the whole-rock La/Yb proxy and observations on crustal deformation. Our results underscore the validity of zircon Eu/Eu* proxy for tracing the evolution of crustal thickness at the batholith or orogen scale, provided that a sufficient number of analyses are obtained. Recent petrologic models questioned the validity of the zircon Eu/Eu* proxy because of the complex interplay among various factors that may affect zircon Eu/Eu*. These models, however, overlooked the interconnections between these factors. In particular, magma redox condition and water content, which are known to significantly impact zircon Eu/Eu*, may also be controlled by differentiation pressure and thus crustal thickness. Therefore, rather than complicating the interpretation, these factors could potentially enhance the pressure control on zircon Eu/Eu*.

Experimental study on reservoir particle migration induced by the injection-production process of underground gas storage

Multi cycle injection and production of underground gas storage (UGS) promote continuous changes in reservoir characteristics, to clarify the impact of different injection and production characteristics on the reservoir, taking carbonate rock fracture-pore type gas storage reservoirs as the research object, established a set of experimental methods based on production characteristics, quantitative analysis of reservoir damage caused by particle migration caused by increasing, decreasing, fluctuating, and reverse changes in production pressure difference. And the following research results are obtained. First, established experimental methods based on production characteristics, the production method includes increasing, decreasing, fluctuating, and reverse changes, realized experimental evaluation of simulating actual production full features. Second, there is a critical pressure difference in the migration of reservoir particles, the fluctuation of production pressure difference induce further migration of particles, resulting in natural unblocking or new blockage. Third, the change in the direction of production pressure difference can cause large particle sizes break into small particle sizes and migrate out of the pore throat, thus the permeability of the reservoir can be improved to a certain extent. It is concluded that controlling a certain production pressure difference during the injection and production process of UGS, not only meets production needs, but also alleviate the damage of injection production to reservoir permeability to a certain extent.

Air Monitoring in Operating Rooms: Results from a Comprehensive Study in the Campania Region

Ensuring air quality in operating rooms is crucial for the health and safety of healthcare professionals and patients. This study, focused on 141 operating theatres in the Campania Region from 2015 to 2022, highlights the importance of air monitoring in operating rooms. Microclimatic parameters, air exchanges, thermal comfort indices, air pressure differences, and anesthetic gas concentrations were measured using standardized procedures. Results indicate that 19% of microclimatic checks exceeded acceptable limits, with significant non-compliance in air velocity (0.01–0.04 m/s, mean 0.03 m/s) and air changes (1–14 h−1, mean 6 h−1). Additionally, levels of anesthetic gases such as nitrous oxide (54.7–197.31 ppm, mean 142.92 ppm) and sevoflurane (2.05–19.45 ppm, mean 5.90 ppm) frequently exceeded recommended exposure limits, raising health concerns. These findings underscore the importance of rigorously adhering to environmental standards and continuously monitoring for optimal conditions in operating rooms. The study also stresses the necessity of ongoing education and training for healthcare personnel on preventive measures to reduce risks. In conclusion, maintaining optimal environmental conditions not only safeguards the comfort and safety of healthcare professionals and patients, but also improves team productivity and clinical outcomes. The study advocates for regularly updating national guidelines and rigorously enforcing safety protocols in healthcare facilities.

Fabrication of three-dimensional bicontinuous porous aluminum by vapor phase dealloying

The development of lightweight, high-specific-surface-area, and exceptionally tough porous aluminum (Al) through dealloying has been consistently captured the attention of the porous metal field. However, widely employed dealloying approaches such as electrochemical dealloying (ECD) and liquid metal dealloying (LMD) face limitations in constructing porous metals with high chemical reactivities. In this study, we employed an emerging vapor phase dealloying (VPD) method, utilizing the differences in saturated vapor pressures among alloy constituents to selectively remove elements with high vapor pressures under optimized temperature and vacuum conditions. The VPD process, characterized by its chemical-free nature and the application of high temperatures, rapidly produces porous Al with varying ligament sizes from the MgZnAl system. The resulting porous Al, distinguished by its crack-free structure and substantial ligament size, exhibits remarkable toughness. The successful fabrication of porous Al using the VPD method effectively bridges the existing gap in generating porous metals with low melting points and high chemical reactivity through ECD and LMD methods. This advancement holds significance for broadening the range of systems and application fields for porous metals.

Deletion of the endothelial glycocalyx component endomucin leads to impaired glomerular structure and function.

Endomucin (EMCN), an endothelial-specific glycocalyx component, was found to be highly expressed by the endothelium of the renal glomerulus. We reported an anti-inflammatory role of EMCN and its involvement in the regulation of vascular endothelial growth factor (VEGF) activity through modulating VEGF receptor 2 (VEGFR2) endocytosis. The goal of this study is to investigate the phenotypic and functional effects of EMCN deficiency using the first global EMCN knockout mouse model. Global EMCN knockout mice were generated by crossing EMCN-floxed mice with ROSA26-Cre mice. Flow cytometry was employed to analyze infiltrating myeloid cells in the kidneys. The ultrastructure of the glomerular filtration barrier was examined by transmission electron microscopy, while urinary albumin, creatinine, and total protein levels were analyzed from freshly collected urine samples. Expression and localization of EMCN, EGFP, CD45, CD31, CD34, podocin, albumin, and α-smooth muscle actin were examined by immunohistochemistry. Mice were weighed regularly, and their systemic blood pressure was measured using a non-invasive tail-cuff system. Glomerular endothelial cells and podocytes were isolated by fluorescence-activated cell sorting for RNA-seq. Transcriptional profiles were analyzed to identify differentially expressed genes in both endothelium and podocytes, followed by gene ontology analysis of up- and down-regulated genes. Protein levels of EMCN, albumin, and podocin were quantified by Western blot. EMCN -/- mice were viable with no gross anatomical defects in kidneys. The EMCN -/- mice exhibited increased infiltration of CD45 + cells, with an increased proportion of Ly6G high Ly6C high myeloid cells and higher VCAM-1 expression. EMCN -/- mice displayed albuminuria with increased albumin in the Bowman's space compared to the EMCN +/+ littermates. Glomeruli in EMCN -/- mice revealed fused and effaced podocyte foot processes and disorganized endothelial fenestrations. We found no significant difference in blood pressure between EMCN knockout mice and their wild-type littermates. RNA-seq of glomerular endothelial cells revealed downregulation of cell-cell adhesion and MAPK/ERK pathways, along with glycocalyx and extracellular matrix remodeling. In podocytes, we observed reduced VEGF signaling and alterations in cytoskeletal organization. Notably, there was a significant decrease in both mRNA and protein levels of podocin, a key component of the slit diaphragm. Our study demonstrates a critical role of the endothelial marker EMCN in supporting normal glomerular filtration barrier structure and function by maintaining glomerular endothelial tight junction and homeostasis and podocyte function through endothelial-podocyte crosstalk.

Flow field analysis and flow prediction of pressure reducing valves in power-law media

A robust hydraulic system is necessary for industrial gluing equipment in order to transfer and regulate a variety of chemical fluid media. Certain operational conditions call for a certain flow output. In hydraulic systems, pressure reduction valves are frequently employed to regulate flow and pressure output. In order to analyze the flow of high viscosity special media inside the valve body, a colloidal medium that complies with the power-law constitutive law and a novel type of pressure-reducing valve appropriate for high viscosity fluids were chosen as the research objects in this study. First, the valve channel's flow performance and flow field characteristics were researched with a combination of simulation and experiments. Then the impact of pressure differences, opening, and temperature variations on flow rate was investigated. The proposed flow prediction formulas can be used to forecast the flow rate in engineering applications accurately which is verified by the comparison of the numerical and experimental results. Lastly, an analysis was done on the pressure reducing valve's capacity to regulate pressure under various operating circumstances. The research can offer a specific reference for the analysis of flow field characteristics inside valves in high viscosity media and the design of pressure-reducing valve bodies in non-Newtonian media. Furthermore, the research results can help determine whether the pressure reducing valve's operating condition is normal.

Alfentanil versus fentanyl for emergency department rapid sequence induction with ketamine: A-FAKT, a pilot randomized trial

BackgroundFentanyl is often administered during rapid sequence induction of anesthesia (RSI) in the emergency department (ED) to ameliorate the hypertensive response that may occur. Due to its more rapid onset, the use of alfentanil may be more consistent with both the onset time of the sedative and the commencement of laryngoscopy. As such, we compared the effect of alfentanil and fentanyl on post-induction hemodynamic changes when administered as part of a standardized induction regimen including ketamine and rocuronium in ED RSI. MethodsThis was a double-blind pilot randomized controlled trial of adult patients requiring RSI in the ED of three urban Australian hospitals. Patients were randomized to receive either alfentanil or fentanyl in addition to ketamine and rocuronium for RSI. Non-invasive blood pressure and heart rate were measured immediately before and at two, four, and six minutes after induction. The primary outcome was the occurrence of at least one post-induction systolic blood pressure outside the pre-specified range of 100-160mmHg (with adjustment for patients with baseline hypertension). Secondary outcomes included hypertension, hypotension, hypoxia, first-pass intubation success, 30-day mortality, and the pattern of hemodynamic changes. ResultsA total of 61 patients were included in the final analysis (31 in the alfentanil group and 30 in the fentanyl group). The primary outcome was met in 58% of the alfentanil group and 50% of the fentanyl group (difference 8%, 95% confidence interval: -17% to 33%). The 30-day mortality rate, first-pass success rate, and incidences of hypertension, hypotension, and hypoxia were similar between the groups. There were no significant differences in systolic blood pressure or heart rate between the groups at any of the measured time-points. ConclusionAlfentanil and fentanyl produced comparable post-induction hemodynamic changes when used as adjuncts to ketamine in ED RSI. Future studies could consider comparing different dosages of these opioids.

TECTONIC AND NON-TECTONIC MESO-STRUCTURES IN THE LISAN FORMATION AND EQUIVALENT RECENT SEDIMENTS OF THE JORDAN RIFT VALLEY-CHARACTERIZATION AND FORMATION MECHANISMS

In this study, the structural elements portrayed in the recent sediments of the Dead Sea, which became exposed at its shores due to the drop in its level are described, and the mechanisms leading to their formation are elaborated. These structures include Plumes and density inversions, subaquatic gliding, seismites, undulations and wavy structures, flexures, and overpressure structures. The formation of these structures is found to be the result of different triggering factors such as Earthquakes, tectonic activity, instability of slopes, density inversion, pore fluids overpressure resulting from gas production by biochemical processes within the sediments (sulfur bacteria reduction of sulfates and oxidation of organic matter (petroleum residues)), submarine groundwater discharge, and volume changes associated with the transformation of gypsum to basinite and anhydrite, and the reversal of that transformation. Each of these triggering factors can produce more than one type of structure, depending on the prevailing composition of the sediments, its layering attitudes, grain-size distribution, porosities, and differential pressure situations within the sediment packages. The main finding of the study is the clarification of the role of gas production within the sediments as a result of sulfur bacteria activity and of the volume change processes associated with the transformation of gypsum to anhydrite and the reversal of that transformation in the formation of the mesostructures of the Dead Sea sediments.

Insights into the Injectivity and Propagation Behavior of Preformed Particle Gel (PPG) in a Low-Medium-Permeability Reservoir.

Heterogeneous phase combined flooding (HPCF) has been a promising technology used for enhancing oil recovery in heterogeneous mature reservoirs. However, the injectivity and propagation behavior of preformed particle gel (PPG) in low-medium-permeability reservoir porous media is crucial for HPCF treatment in a low-medium-permeability reservoir. Thus, the injectivity and propagation behavior of preformed particle gel in a low-medium-permeability reservoir were systematically studied by conducting a series of sand pack flooding experiments. The matching factor (δ) was defined as the ratio of the average size of PPG particles to the mean size of pore throats and the pressure difference ratio (β) was proposed to characterize the injectivity and propagation ability of PPG. The results show that with the increase in particle size and the decrease in permeability, the resistance factor and residual resistance factor increase. With the increase in the matching factor, the resistance factor and residual resistance factor increase. The higher the resistance factor and residual resistance factor are, the worse the injectivity of particles is. By fitting the relationship curve, PPG injection and propagation standards were established: when the matching coefficient is less than 55 and β is less than 3.4, PPG can be injected; when the matching coefficient is 55-72 and β is 3.4-6.5, PPG injection is difficult; when the matching coefficient is greater than 72 and β is greater than 6.5, PPG cannot be injected Thus, the matching relationship between PPG particle size and reservoir permeability was obtained. This research will provide theoretical support for further EOR research and field application of heterogeneous phase combined flooding.