Cumulative Volume Research Articles

The 5-factor modified frailty index as a prognostic factor for stereotactic radiosurgery in meningioma management.

Meningiomas are the most frequent primary intracranial malignancy. While surgical resection can confer long term tumor control, stereotactic radiosurgery (SRS) is often used for small, asymptomatic tumors in the adjuvant setting. Frailty has been associated with increased rates of peri-operative morbidity but has yet to be defined in the setting of SRS for meningiomas. We therefore sought to examine the relationship between frailty and clinical/radiographic outcomes of patients with meningiomas who have undergone SRS. A single-center, retrospective cohort study classified patients by their 5-factor modified frailty index (mFI-5) score into pre-frail (0-1) and frail (2-5) at the time of SRS treatment. Evaluations of overall survival (OS), progression free survival (PFS), local control (LC), and distant control (DC) were performed using Kaplan-Meier analysis. Cox proportional hazards regression analysis was used to further define factors associated with OS/PFS. 94 patients met inclusion criteria and underwent SRS for meningioma treatment from 2019 to 2023. Analyses compared prefrail (0-1) and frail (2-5) individuals. Kaplan-Meier analysis demonstrated a near significant association between frailty and OS (HR 3.66, 95% CI 0.49-26.8 p = 0.05) with 3-year OS rates of 75.4% in the pre-frail versus 36.6% in the frail group. However, a significant relationship was demonstrated between frailty and PFS (HR: 2.95 95% CI 1.12-7.81, p = 0.02) with 3-year PFS rates of 90.5% in the pre-frail group versus 49.2% in the frail group. Univariable regression analysis demonstrated that frailty, prior surgical excision, and cumulative tumor volume predicted PFS. Frailty, as assessed by the mFI-5, did not independently predict OS but did predict PFS in individuals with meningioma undergoing SRS.

Effect of diet combined with exercise intervention on tumor necrosis factor α in overweight or obese groups: Based on the exercise dose-response relationship

Background: Chronic low-grade systemic inflammation, often linked to obesity or being overweight, is associated with various complications and an increased risk of disease development. Tumor necrosis factor α (TNF-α) is a key inflammatory factor that significantly impacts various body functions. Objective: 1) To assess whether combined interventions are more effective than single interventions in combining diet and exercise. 2) To assess the effectiveness of exercise dose in different interventions on tumor necrosis factor (TNF-α) levels in obese or overweight patients. Methods: A thorough search was conducted across four electronic databases of randomized controlled trials that focus on exercise or dietary interventions for patients with obesity or overweight. This comprehensive review encompasses data collected up to August 2024. Two independent researchers conducted a thorough evaluation of the literature's quality. Network and dose-response analyses were performed using random effects models to examine the impact of diverse interventions on TNF-α. Results: A total of 19 randomized controlled trials with 1479 patients with obesity or overweight were included. The meta-analysis showed that the hypocaloric diet combined with aerobic training (HDAT) possessed the highest ranking (SMD= -1.00,95%CI -1.51 to -0.49), followed by the hypocaloric diet (HD) (SMD= -0.40,95%CI -0.89 to 0.09), hypocaloric diet combined with resistance training (HDRT) (SMD= -0.48,95%CI- 1.43 to 0.48), and aerobic training combined with resistance training (ART) (SMD= -0.18,95%CI -0.92 to 0.57). Additionally, a notable improvement in TNF-α levels was observed in individuals adhering to a hypocaloric diet in conjunction with exercise when the cumulative exercise volume reached 150 metabolic equivalent of task minutes per week. Conclusion: Based on the GRADE rating guidelines, moderate-quality research evidence indicates that a hypocaloric diet combined with aerobic training (HDAT) is the most effective intervention for enhancing tumor TNF-α levels in individuals with obesity or overweight. Additionally, the dose-response relationship was observed between the total exercise dose and TNF-α levels. Future research should investigate the specific effects of various aerobic exercise modalities on TNF-α levels in obese or overweight patients to develop a more personalized approach to exercise prescription.

Thermal analysis and kinetic investigation of using a hybrid adsorption-hydration method to promote CO2 capture

In this work, a hybrid adsorption-hydration method was utilized to promote CO2 capture. The CO2 capture performance in the fixed bed of coal particles was assessed at various water saturations (0 %, 20 %, 40 %, 70 %, and 100 %), 277.15 K, and 3.2 MPa. It was found that gas consumption at 100 % water saturation increased by 45 % compared to that at 0 % water saturation (dry coal particles). Moreover, as the water saturation increased, CO2 capture became dominated by hydrate formation rather than gas adsorption. The thermal analysis for CO2 capture at 0 % and 100 % water saturation detected the exothermic peaks associated with CO2 adsorption and CO2 hydrate formation, as well as the endothermic peaks corresponding to CO2 desorption and CO2 hydrate dissociation. This confirms that CO2 capture in the fixed bed of water-saturated coal particles consists of CO2 adsorption followed by hydrate formation. The morphologies of CO2 hydrate formation in the fixed bed of 100 % water-saturated coal particles were observed, and the mechanism of CO2 capture using the hybrid adsorption-hydration method was illustrated based on the thermal analysis and kinetic investigations. It was also found that after the adsorption-hydration process, the average cumulative pore volume of the coal particles decreased by 14.47 % compared to the original coal particles, and the micropores and mesopores were predominantly affected. Therefore, utilizing the hybrid adsorption-hydration process in a fixed bed of coal particles provides a promising method to enhance CO2 capture.

Pre-emptive use of glucose 5% as the standard drug solvent reduces hypernatremia in critically ill patients

Abstract Background Hypernatremia presents a common complication in ICU patients, associated with increased mortality and length of stay. This study investigates the effect of sodium chloride 0.9% compared with glucose 5% solution as the standard intravenous drug diluent on the prevalence of hypernatremia in a medical ICU. Methods This is a retrospective before-and-after study comparing two consecutive patient groups before- and after the standard drug solvent was changed from sodium chloride 0.9% to glucose 5% solution for compatible medications. A total of 265 adult COVID-19 patients admitted between October 2020 and March 2021 to the study intensive care unit were included, with 161 patients in the timeframe when sodium chloride 0.9% was employed as the standard drug solvent and 104 patients when glucose 5% was used. Routine sodium measurements from arterial and venous blood gases, along with heparinized lithium plasma, were analyzed. The daily sodium concentrations and the prevalence of severe hypernatremia (>150 mmol/l) were assessed during the first 8 days after ICU admission. Results Baseline characteristics were similar between the two groups. The cumulative volume of intravenous drug diluents was comparable. In the glucose 5% group, about half of the total drug diluent volume was glucose 5% (mean [SD]: 2251.6 [2355.4] mL), compared to 135.0 [746.9] mL (p < 0.001) in the control group. Average sodium concentrations diverged after day two, with the glucose 5% group consistently showing lower sodium levels (mean difference of approximately 2.5 mmol/L). Severe hypernatremia occurred less frequently in the glucose 5% group (6.6% vs. 20%). Conclusion Glucose 5% solution as the standard intravenous drug solvent significantly reduced sodium concentrations and the occurrence of severe hypernatremia. This simple modification in solvent choice may serve as a preventive strategy against hypernatremia in the ICU. Further prospective research is necessary to determine associated clinical outcomes. Trial registration: The trial was registered in the German Clinical Trials Register (DRKS00031877).

Influence of silica fume on pore structure, mechanical properties and carbon emission of reactive powder concrete prepared by ice crystal homogenization technology

Under ultra-low water-to-binder ratio conditions, the liquid-bridge effect between powders seriously restricts the development of reactive powder concrete (RPC). Ice crystal homogenization technology fundamentally solves the liquid-bridge problem between powders. However, high carbon emissions still constrain the application of RPC. This paper introduces an innovative RPC material incorporating silica fume (SF) as a supplementary cementitious material to solve environmental concerns and alleviate powder aggregation challenges based on the ice crystal homogenization technology. Experimental results show that there was a significant improvement in compressive and flexural strengths observed, particularly in RPC material containing 15% SF, which exhibited the most notable enhancements: a 19.7% increase in compressive strength to 296.3MPa and a 23.6% increase in flexural strength to 43.8MPa. Moreover, the optimized microstructure was reflected in a substantial reduction in water absorption rate and cumulative pore volume by 44.7% and 54.4%, respectively. Besides, RPC incorporating 15% SF achieved the lowest carbon emissions efficiency, with carbon emissions efficiency could be reduced by 79%~93% compared with conventional UHPC. In conclusion, the use of SF and ice crystal homogenization technology in RPC provides the great potential for developing sustainable construction materials and promoting carbon reduction strategies.

Rheo-impedance behavior of cellulose nanofibers produced by mechanical processing

AbstractCNFs are one of the renewable and the sustainable resources with low environmental impact and have various characteristics such as increased strength and weight reduction when added to resins. Since CNFs are one of the new materials that can fulfill the goals of the Sustainable Development Goals (hereafter abbreviated as SDGs), many researchers have been studying the nano-fibrillation of wood fibers. From the viewpoint of SDGs, it is necessary to avoid using a large amount of chemical agents and consuming a large amount of energy for the production of CNFs. To realize these requirements, it is important to find a way to industrially utilize CNFs containing insufficiently nanosized fibers, and for these purposes, it is essential to evaluate the physical properties of these CNFs from multiple perspectives. Cellulose fibers are intrinsically insulating materials, but how their electrochemical properties are changed by nano-fibrillization has been little studied. Therefore, we decided to clarify the relationship between the size of CNFs and the electrochemical impedance properties of the CNF suspensions containing un-fibrillated fibers, which were prepared by a wet refinement system. The fiber diameter remained constant as the number of mechanical treatments (hereafter referred to as the “number of collisions”) increased. On the other hand, the cumulative medium volume diameter, D50, defined as the apparent fiber length (hereafter referred to as the “fiber length”, in microns), significantly decreases with the increasing number of collisions. The rheo-impedance |Z| of the CNF suspension remained nearly constant in the intermediate frequency range of 103–106 Hz, even if the internal structure of the system was deformed by the increasing shear rate. This means that the electrochemical properties of the CNFs are independent of the changes in the macroscopic aggregation structure. Furthermore, the internal resistance R1 calculated from the impedance |Z| characteristics (Nyquist plot) became decreased with the increasing number of collisions, indicating a proportional relationship between the resistance R1 and the CNF fiber length, D50. This suggests that R1 related to the resistance caused by the electrolyte in the suspensions or the protons dissociated by the hydration of the hydroxyl groups of the cellulose molecule as they move across the gaps between the microfibrils. Based on these results, it appears that the electrochemical properties of the CNF suspensions are independent of the changes in the macroscopic aggregation structure and simply depend on the fiber length, in other words, the electrochemical properties are a useful method for indirectly evaluating the fiber length of the CNFs.

Enhanced biogas production from municipal solid waste via digestion with cow manure: A case study

Abstract Anaerobic digestion (AD) of feedstocks yields biogas, a potentially useful new energy source. This study looked into the anaerobic co-digestion of cow dung and organic garbage to produce biogas. An anaerobic biodigester, with a volume of 20 L, was used to digest organic waste (OW) and to trace the changes that occur during the AD process. It was equipped with tools that ensure complete control of the conditions affecting anaerobic biological reactions such as temperature, pH function, and mixing speed. Therefore, an anaerobic biodigester was designed to contain such biological transformations and to improve the biogas production process from OW. Based on the present investigation, the AD of OW was improved by integrating the substrate with sewage sludge or cow manure (CM) during the digestion process to provide the basic microorganisms to complete the digestion process. Feeding into the digester was a blend of 100 kg of cow dung (CM) and OW per day, diluted 1:1 with water. A gasbag was used to capture the methane that resulted. Biogas production began on the seventh day after the substrate was fed into the digester. A performance test was carried out on the produced biogas to determine its composition. For OW–CM, the generated biogas’s methane (CH4) concentration was determined to be 60%, but the rates of decline for TS and VS were 57 and 50.6%, respectively. Anaerobic biodegradation of OW–CM experiments was observed at 37°C, a mesophilic temperature. For OW–CM, the pH value was 6.7. After being adjusted to standard circumstances, the cumulative volume of methane produced which had been recorded as 4,914 mL became 3964.5 mL.

Irrigation of rangeland soils with coal seam water - A lysimeter study on soil physico-chemical properties

Groundwater extracted from coal seams may be a resource for irrigation of land in areas with low rainfall, but the effect of this water on soil properties needs to be established. A lysimeter study was conducted using intact soil cores (0.75 m diameter, 1.4 m deep) of four different soil types (Sodic Vertisol, Calcic Solonetz, Haplic Solonetz and Xanthic Lixisol) from southern Queensland, Australia, to study changes in soil physical and chemical properties under accelerated rates of irrigation with coal seam (CS) water (electrical conductivity (ECw) of 3 dS/m, pH of 8.8, and a sodium adsorption ratio (SAR) of 100). Cores were also alternately irrigated with deionised water to simulate rainfall, and either lucerne (Medicago sativa L) or Rhodes grass (Chloris gayana Kunth.) where grown in the lysimeters. The soil surface was treated with stoichiometric rates of elemental sulfur (1.4 t/ha) and gypsum (2.5 t/ha) prior to every 450 mm CS water irrigation to minimise changes in SAR and pH. Three of the soils (Vertisol, both Solonetz) had low leaching fractions (≤ 0.1 %) due to their clay texture and were initially saline in the subsoil (ECse 1.4–4.4 dS/m). Irrigation with CS water resulted in a gradual increase in salt content (EC) and SAR throughout the soil profile, but pH was not increased due to surface-applied elemental sulfur. The Lixisol had a higher hydraulic conductivity and leaching fraction (6.7 %) due to is loamy texture – in this soil, accumulated salts could be leached and no increase in salinity or pH were measured. Despite an increase in SAR for this loamy soil, no structural degradation was observed, and it could be sustainably irrigated with up to 3200 mm CS water (with cumulative irrigation volume of 5400 mm). Hence, leaching fractions rather than soil chemistry are good indicators to identify soils suitable for irrigation with CS water that is saline, alkaline, and sodic.

Simulation Study on Reservoir Stimulation of Multihorizontal Wells for Gas Hydrate Production in Low-Permeability Reservoirs.

The feasibility of hydrate exploitation technology has been verified by two rounds of trial productions in the South China Sea, but it is also faced with the problem of low gas production efficiency. Therefore, this paper proposed four different hydrate production cases with multihorizontal wells and established simulation models. Then, the influence patterns of reservoir stimulation and offset distances on hydrate dissociation, saturation change, and pressure distribution were studied. To understand hydrate dissociation behaviors and production performances, the coupling effects of multihorizontal wells were discussed. Through simulation, the following conclusions could be drawn: (1) hydrate reservoir stimulation could effectively increase gas production. In these four production models, the cumulative gas production in Case C (multihorizontal wells + reservoir stimulation) was 5.27 times that of Case A (only multihorizontal wells) in 330 days. However, in Case D with screen completions, the gas output was 15.58% less compared with Case C. (2) Different offset distances of horizontal wells had a relatively minor impact on the cumulative gas yield and daily gas capacity. In addition, the variation range of hydrate saturation changed with offset distances of horizontal wells, indicating that hydrate dissociation occurred mainly around horizontal wells and fractures. (3) Considering interwells coupling, the daily gas rate and cumulative gas production of inner wells were higher than outer wells, and the cumulative gas volume increased by 6.4% in 330 days. Temporally and spatially, the hydrate saturation variation between wells was significantly faster than the outward expansion from the horizontal wells. Moreover, nearer to the axis of the horizontal wells, the variation in the hydrate saturation was more pronounced. These results could provide theoretical data to optimize marine hydrate development with multihorizontal wells.

Salvianolic acid B improves the microcirculation in a mouse model of sepsis through a mechanism involving the platelet receptor CD226.

Salvianolic acid B (SalB) demonstrates diverse clinical applications, particularly in cardiovascular and cerebral protection. This study primarily investigated the effects of SalB on sepsis. The model of sepsis via caecal ligation puncture (CLP) was established in male C57BL/6 mice. Therapeutic effects of SalB on hepatic and pulmonary injury, inflammatory responses and microcirculatory disturbances in sepsis were evaluated. Platelet aggregation and adhesion were measured via flow cytometry and an adhesion test. After overexpression of platelet-related activating molecules by 293T cells, the efficient binding of SalB and platelet CD226 molecules was further evaluated. Finally, neutralizing antibody experiments were used to assess the mechanism of SalB in alleviating the progression of sepsis. SalB mitigated hepatic and pulmonary impairments, reduced inflammatory cytokine levels and enhanced mesenteric microvascular blood flow in septic mice. SalB enhanced CLP-induced reduction of platelet count and platelet pressure cumulative volume. SalB reduced platelet adhesion to endothelial cells and platelet aggregation to leukocytes. A high binding efficiency was observed between SalB and the platelet adhesion molecule CD226. Ex vivo, interactions between SalB and platelets from CD226-knockout mice were markedly decreased. In vivo administration of CD226 neutralizing antibodies significantly delayed disease progression and enhanced mesenteric microcirculation in septic mice. In our murine model of sepsis, treatment with SalB improved the microcirculatory disturbance and hindered the progression of sepsis by inhibiting platelet CD226 function. Our results suggest SalB is a promising therapeutic approach to the treatment of sepsis.

Effect of Isotropic and Anisotropic Permeability on Gas Production Behavior of Site NGHP-01-10D in Krishna-Godavari Basin

This study reports an investigation into both isotropic and anisotropic permeability effects on gas production behavior during depressurization-induced natural gas hydrate dissociation at site NGHP-01-10D in the Krishna-Godavari basin. Numerical simulations were performed on a reservoir-scale model incorporating a single vertical well, examining different scenarios of permeability ratios (rrz). The investigation assessed gas and water production rates, cumulative production volumes, the gas-to-water ratio, and the spatial distribution of reservoir parameters throughout a production duration of 3 years. The findings indicate that permeability anisotropy has a substantial impact on hydrate dissociation and gas recovery. For rrz > 1, horizontal pressure propagation was promoted and gas production increased. For example, at t = 1100 days, the total gas production improved from 7.88 × 105 ST m3 for rrz = 1 to 55.9 × 105 ST m3 for rrz = 10. For rrz < 1, vertical pressure propagation resulted in higher water production with concomitantly lower rates of gas production rates. Spatial distribution analysis revealed that higher rrz values led to more extensive radial propagation of pressure drop, temperature decrease, gas saturation increase, and hydrate dissociation. The study concludes that higher horizontal permeability enhances depressurization effects, resulting in higher gas production rates and more favorable gas-to-water ratios.

Quality of life after stereotactic radiosurgery for brain metastasis: an assessment from a prospective national registry.

Stereotactic radiosurgery (SRS) is frequently used in the management of brain metastasis patients. However, there is an urgent need to evaluate post-treatment outcomes and quality of life metrics for patients undergoing SRS for brain metastases. The NeuroPoint Alliance (NPA) SRS Quality Registry conducted prospective enrollment of patients undergoing SRS from 2017 to 2024. Patients with brain metastases from lung cancer, breast cancer, and melanoma were included in the analysis. Outcomes of interest included quality of life metrics, as captured by the five-dimension Euro-QOL (EQ-5D) at 6-12 months and last record follow-up, overall survival, local progression, out-of-field progression, and overall intracranial progression. 522 patients comprised our analytic cohort, and 315 patients had available EQ-5D data at the time of SRS and final follow-up. 264 (47.8%), 197 (35.7%), and 91 (16.5%) patients had 1, 2-4, and 5-14 lesions pre-SRS, respectively. The median overall survival time from diagnosis was 27.3 months. The median time-to-local progression was not reached. At final follow-up, 107 (34.0%) patients had improvement, 51 (16.2%) patients had stable, and 113 patients (35.9%) had worsening EQ-5D scores when compared to baseline. For 44 (13.9%) patients mixed responses across the EQ-5D indices were reported. Linear regression analysis showed that male sex, smoking status, primary tumor type, time-to-overall progression, cumulative intracranial tumor volume (CITV), and baseline EQ-5D were statistically significantly associated with EQ-5D single index at the final follow-up. Real-world data from the SRS NPA Registry demonstrated that most patients with brain metastasis had no change or improvement in quality of life after SRS. Baseline EQ-5D was predictive of EQ-5D single index at final follow-up, and, as such, EQ-5D at baseline would be a valuable assessment measure for brain metastasis patients undergoing SRS.

A coupled displacement-pressure model for elastic waves induce fluid flow in mature sandstone reservoirs

Elastic (seismic) wave stimulation is considered one of the unconventional enhanced oil recovery (EOR) methods. Increasing water quantity in the high permeability layer of a mature oil reservoir is highly challenging and can significantly decrease the ultimate recovery due to the reservoir heterogeneity. Using seismic waves can be considered low-cost, environmentally friendly, and illuminates the entire reservoir size compared to conventional EOR methods. A numerical model is developed by extending the Quintal approach for seismic attenuation due to wave-induced fluid flow (WIFF) to incorporate capillary pressure in partially saturated porous media and shift undrained boundary conditions to exclude external flow stress for drained boundary conditions. Therefore, the fluid distribution due to the capillary effect makes the developed finite element method (FEM) u-p model more widely applicable for oil recovery in mature reservoirs. A two-layer partially saturated media was subjected to compressive seismic stress at low frequency (3 Hz). The results indicated that the vertical displacement gradients of the bottom and upper layers decline with excitation time for both fully and partially saturated media. On the other hand, partially saturated pore pressure gradients of both the upper and bottom layers have higher amplitudes with excitation time than fully saturated pore pressure gradients due to the influence of capillar pressure. The cumulative crossflow oil volume for 180 days of continuous stimulation was 1176 bbl, 1032 bbl, and 648 bbl in low permeability layers: 200 md, 100 md, and 50 md, respectively. Therefore, the developed model has the potential for field-scale EOR applications. The study also suggests coupling elastic EOR with CO2 flooding to recover more oil due to increasing fluid mobility and relative permeability to oil in low-permeability reservoirs or tight formations.

Implementation of Smart Farm Systems Based on Fog Computing in Artificial Intelligence of Things Environments.

Cloud computing has recently gained widespread attention owing to its use in applications involving the Internet of Things (IoT). However, the transmission of massive volumes of data to a cloud server often results in overhead. Fog computing has emerged as a viable solution to address this issue. This study implements an Artificial Intelligence of Things (AIoT) system based on fog computing on a smart farm. Three experiments are conducted to evaluate the performance of the AIoT system. First, network traffic volumes between systems employing and not employing fog computing are compared. Second, the performance of the communication protocols-hypertext transport protocol (HTTP), message queuing telemetry transport protocol (MQTT), and constrained application protocol (CoAP)-commonly used in IoT applications is assessed. Finally, a convolutional neural network-based algorithm is introduced to determine the maturity level of coffee tree images. Experimental data are collected over ten days from a coffee tree farm in the Republic of Korea. Notably, the fog computing system demonstrates a 26% reduction in the cumulative data volume compared with a non-fog system. MQTT exhibits stable results in terms of the data volume and loss rate. Additionally, the maturity level determination algorithm performed on coffee fruits provides reliable results.

Tumor Volume Doubling Time of Less Than One Year is Associated with a Higher Risk of Death from Medullary Thyroid Cancer.

Tumor volume doubling time (TVDT) is emerging as a useful tool in predicting oncologic outcomes. There is limited data on the prognostic role of TVDT in metastatic medullary thyroid cancer (MTC). The goal of this study was to assess the value of TVDT in predicting disease-specific survival (DSS) in patients with hereditary and sporadic MTC. This was an Institutional Review Board-approved cohort study including patients with metastatic MTC having at least 3 consecutive imaging studies. TVDT of up to the five largest lesions per organ was calculated using a standardized formula. The association between TVDT and DSS was analyzed using Kaplan-Meier survival curves. Cox proportional regression model was used to account for confounding factors. The study sample consisted of 51 patients presenting with 286 metastatic lesions measured with 457 scans during the follow-up of 51 (IQR 25-102) months. Median age was 19 years (IQR 15-41), 53% female patients. Cumulative volumes of all metastatic lesions and proportion of patients with TVDT of <1 year were higher in patients with sporadic as compared with hereditary MTC (p<0.01). Factors independently associated with shorter DSS were TVDT of <1 year based on 3 initial and 3 last scans as well as lung, brain and prostate as the organs with the fastest growing tumor. TVDT based on 2-dimentional and 3-dimentional measurements showed strong correlation (r=0.94, p<0.05). Three baseline and three most recent scans preceding follow-up visit enable calculation of TVDT and can be used as predictors of mortality from MTC.

Projection segmentation-based image recognition technology for automatic reading of gas meter

In view of the shortcomings of the existing gas meter reading methods, this paper introduces an automatic reading method and calibration device based on the projection segmentation method, which uses the color difference between the character part and the rest part of the last code wheel of the gas meter counter to realize image recognition of the turned characters, and then calculates the cumulative volume indication of gas meter based on the number of turned characters. The pixel projection value scanned by the camera device at the horizontal centerline of the last code wheel changes alternately when the code wheel rotates. The proposed projection segmentation method does not require recognition of specific characters, simplifying the algorithm and making it suitable for most calibration devices. Experiments show that the accuracy rate of the proposed method is 100% even under low-light conditions, which is a great improvement compared with the traditional character recognition method. Additionally, the reading resolution of the proposed method is improved by 10 times compared with the existing photoelectric sampling method and template matching method, and the total calibration time can be reduced by 6.7%–58.7%, which significantly enhances the calibration efficiency.

Systematic experiment on adsorption, separation and regeneration of X zeolites for LNG production with different regeneration strategies: vacuum, purging, heating and hybrid combinations

This work experimentally investigated the adsorption, separation and regeneration properties of two X zeolites for natural gas deep decarbonization in liquified natural gas (LNG) production. The regeneration properties of JLOX500 and 13X were compared with relation to regeneration efficiency, energy consumption, desorption and adsorption rate of CO2, and other factors in different pathways: vacuum, purging, heating, and hybrid combinations. The results demonstrated that fresh JLOX500 with more cations and less binders had significantly greater CO2 adsorption capacities and larger separation factor (CO2/CH4) than those of fresh 13X, because of its larger micro-porosity and higher CO2 isosteric heat. Due to higher partial pressure, the adversely significant effect of CH4 competing adsorption against CO2 on adsorbent regeneration is confirmed. The flow rate increases of purge gas had no effects on regeneration efficiency for 13X when the CO2 concentration of desorbed gas reached to zero. Because of a greater cumulative pore volume, JLOX500 after sufficient regeneration has a larger CO2 adsorption capacity and a higher desorption rate of CO2 than 13X, which also makes it more efficient with regards to purge gas and energy consumption utilization. With 150 mL/min of purge gas, the energy consumptions for 13X and JLOX500 regenerated at 150 °C were 4.20 and 2.89 MJ/kg-CO2, respectively. The CH4 recovery relied on the regeneration efficiency of adsorbents, duration of adsorption, and the amount of purge gas used. Both X zeolites regenerated by purging (150 mL/min) or vacuuming at 1 kPa at 150°C could purify the feed to the CO2 content less than 50 ppm, but JLOX500 is more efficient with regards to the overall performance.

Early wave reflection of carotid artery is associated with 18F-FDG PET hypometabolism in Alzheimer's brain areas of cognitively normal adults.

Arterial stiffening likely plays a role in Alzheimer disease (AD) pathogenesis. The current study investigated whether inter-individual variations in arterial stiffness and pressure wave parameters were associated with 18F-FDG positron emission tomography (PET) metabolism in AD-associated brain areas throughout adulthood, independently of age and before the onset of any neuropsychological disorders. A prospective, large age-range population of 67 patients (17 young, 16 middle-aged, and 34 older adults; 37 women) underwent a: brain 18F-FDG PET, blood pressure recording, and carotid/femoral pulse wave-based measurements, including the time-to-peak of the reflected backward carotid pulse wave (bT), on the same day. Multivariable and quantitative voxel-to-voxel analyses (P-voxel < 0.005, corrected for cluster volumes) were conducted to assess associations between vascular parameters and 18F-FDG PET metabolism in AD-associated brain areas. In the multivariable analysis, only increased age and decreased bT were independently associated with the decline of metabolic activity in AD-associated brain areas (P < 0.001). In the voxel-to-voxel analysis with age as a covariate, bT was strongly associated with the metabolic activity of 40 clusters in AD-associated brain areas (clusters cumulative volume: 63 cm3; T score max: 5.7). In a large age-range population of adult patients, who are still unaffected by neuropsychological disorders, an early reflected arterial pressure wave, as evidenced by a decreased bT value, is strongly associated with hypometabolic activity of AD-associated brain areas, independently of age.

A thermodynamics-based coupled model for multi-phase flowback in deformable dual-porosity shale gas reservoirs

Over the past decades, there has been growing interest in modelling multi-phase flowback in shale gas reservoirs during hydraulic fracturing, primarily due to the significant risk of groundwater pollution. However, the lack of fully coupled simulations and a unified theoretical model has hindered the study of coupled adsorptive hydro-mechanical behaviour and its influence on fluid flowback prediction. In this paper, we have extended the non-equilibrium thermodynamics-based Mixture Coupling Theory to derive the constitutive relationship and governing equation for adsorptive multi-phase fluid flows in deformable dual-porosity media. Helmholtz free energy density has been used to establish the relationship between solids and fluids. The interaction of adsorptive fluids in the pore and fracture space has been fully considered, leading to a new form of constitutive equation, which obtained the molecular adsorptive effect on the rock by introducing adsorption entropy production. The proposed governing equations determine the fully coupled evolution of solid deformation and multi-phase flow, with the consideration of adsorption as well as pore and fracture porosity change. Numerical simulation is then performed to study the flowback of a real shale gas well and the influence of coupled behaviour on model prediction. The simulation shows that the flowback flux is mainly by the fracture (more than 99.9 %) and the overall cumulative volume is 2427.1 m3 within 225 h which accounts for about 5.3 % of the total injected fracturing fluid, and the sensitivity analysis reveals that the manual fracture porosity is the most sensitive factor to the cumulative flowback. This work provides new insights into the flowback process of shale reservoirs in a fully coupled view and the proposed theoretical tool should contribute to the modelling of other adsorptive multi-phase flow problem in deformable dual-porosity media such as carbon storage and coalbed methane production.

Technology and Research on Improving Oil Recovery by Volume Fracturing with Phase Change Permeability in Ultra-low Permeability Reservoirs

Abstract The conventional water injection development production wells in ultra-low permeability reservoirs have low efficiency, low production and low liquid content, and poor economic benefits. Traditional water drive development techniques are difficult to adapt to the requirements of economically effective development in ultra-low permeability reservoirs. Therefore, it is urgent to adjust development ideas and transform water injection development methods. A major development experiment was carried out in the Y284 area of Huaqing Oilfield to transform the water injection development method. Based on the mechanism of reverse osmosis flooding in oil recovery wells, this article uses dynamic monitoring technologies such as downhole microseismic to achieve three-dimensional reservoir transformation, and establishes a large-scale fracturing technology of “collaborative permeability flooding, volume fracturing, and multi-stage temporary plugging” for reverse osmosis wells in ultra-low permeability reservoirs. Research has shown that large-scale fracturing technology for water injection wells can improve single well oil recovery speed by increasing the complexity of fracture networks. The important factors affecting the effectiveness of water injection wells include reservoir properties, fracturing transformation scale, cumulative water injection volume, remaining oil distribution, and heterogeneity of aquifers. At the same time, the construction parameters of large-scale volume fracturing for water injection wells, namely 140-170m, are quantitatively determined based on the actual situation of the mining field &amp;sup3; The amount of sand added, a sand ratio of 17-22%, and a large displacement of 8-10m3/min, 1400-2000m &amp;sup3; The amount of liquid entering the ground can most effectively achieve the conditions for reservoir transformation. The conclusion is that large-scale fracturing technology for conversion wells provides technical support for volume fracturing and optimization design of fracturing parameters for low production wells in ultra-low permeability reservoirs, and can provide guidance and reference for the efficient development of other similar ultra-low permeability reservoirs.