Residual Distribution Research Articles

Analytical and finite element investigation on residual stress analysis for composite thermoplastic cantilever beam under unique load

For a steel-fiber-based low-density homogenous composite thermoplastic cantilever beam, numerical (ANSYS APDL19) and analytical (MATLAB program) for elastoplastic stress distributions are achieved. At its free end, a thermoplastic cantilever structural member is loaded using a steady force. For orientation angles of (0°, 15°, 30°, 45°, 60°, 75° and 90°), the yield region's expansion and (σx)r are calculated. MATLAB program was used to determine the residual distribution of stress analytically. Both the yield zone that expands just at the top surface and the plastic zone that expands on both the top and bottom surfaces simultaneously are subjected to the elastic–plastic analysis. After the applied load has been freed, the components of residual distribution of stress are detected. Additionally, the distributions of the σx residual stress is established. By utilizing residual distribution of stress, the beam can be reinforced. The upper and lower edges of the beam are where the residual stress values are strongest. For the same load in the beam at orientation angles of (0°, 15°, 30°, 45°, 60°, 75° and 90°) the space amidst the free end and the plastically contracted region is determined. Lower discrepancy is evaluated for numerical (ANSYS APDL19) and analytical results.

利用线性回归分析、BP 神经网络与随机森林的枣树灌溉系统设计

This paper evaluates linear regression analysis, BP neural network, and a random forest prediction model for the prediction of jujube water demand. The results highlight that the R2 of the random forest is 0.941 and the residual distribution is the most stable. Hence, the random forest is more suitable for prediction, and therefore, an intelligent irrigation system is established employing random forest, where the cloud server is the upper computer and a Raspberry Pi is the lower computer, and at the same time, a PC and a mobile interface was built to present various information about the developed irrigation system.

Operando neutron diffraction reveals mechanisms for controlled strain evolution in 3D printing

Residual stresses affect the performance and reliability of most manufactured goods and are prevalent in casting, welding, and additive manufacturing (AM, 3D printing). Residual stresses are associated with plastic strain gradients accrued due to transient thermal stress. Complex thermal conditions in AM produce similarly complex residual stress patterns. However, measuring real-time effects of processing on stress evolution is not possible with conventional techniques. Here we use operando neutron diffraction to characterize transient phase transformations and lattice strain evolution during AM of a low-temperature transformation steel. Combining diffraction, infrared and simulation data reveals that elastic and plastic strain distributions are controlled by motion of the face-centered cubic and body-centered cubic phase boundary. Our results provide a new pathway to design residual stress states and property distributions within additively manufactured components. These findings will enable control of residual stress distributions for advantages such as improved fatigue life or resistance to stress-corrosion cracking.

A user independent denoising method for x-nuclei MRI and MRS.

X-nuclei (also called non-proton MRI) MRI and spectroscopy are limited by the intrinsic low SNR as compared to conventional proton imaging. Clinical translation of x-nuclei examination warrants the need of a robust and versatile tool improving image quality for diagnostic use. In this work, we compare a novel denoising method with fewer inputs to the current state-of-the-art denoising method. Denoising approaches were compared on human acquisitions of sodium (23 Na) brain, deuterium (2 H) brain, carbon (13 C) heart and brain, and simulated dynamic hyperpolarized 13 C brain scans, with and without additional noise. The current state-of-the-art denoising method Global-local higher order singular value decomposition (GL-HOSVD) was compared to the few-input method tensor Marchenko-Pastur principal component analysis (tMPPCA). Noise-removal was quantified by residual distributions, and statistical analyses evaluated the differences in mean-square-error and Bland-Altman analysis to quantify agreement between original and denoised results of noise-added data. GL-HOSVD and tMPPCA showed similar performance for the variety of x-nuclei data analyzed in this work, with tMPPCA removing ˜5% more noise on average over GL-HOSVD. The mean ratio between noise-added and denoising reproducibility coefficients of the Bland-Altman analysis when compared to the original are also similar for the two methods with 3.09 ± 1.03 and 2.83 ± 0.79 for GL-HOSVD and tMPPCA, respectively. The strength of tMPPCA lies in the few-input approach, which generalizes well to different data sources. This makes the use of tMPPCA denoising a robust and versatile tool in x-nuclei imaging improvements and the preferred denoising method.

SDORP: SDN Based Opportunistic Routing for Asynchronous Wireless Sensor Networks

In wireless sensor networks (WSNs), it is inappropriate to use conventional unicast routing due to the broadcast storm problem and spatial diversity of communication-links. Opportunistic-Routing (OR) benefits the low duty-cycled WSNs by prioritizing the multiple candidates for each node instead of selecting one node as in conventional unicast-routing. OR reduces the sender waiting time, but it also suffers from the duplicate packets problem due to multiple candidates waking up simultaneously. The number of candidates should be restricted to counterbalance between the sender waiting time and duplicate packets. In this paper, software-defined networking (SDN) is adapted for the flexible management of WSNs by allowing decoupling of the control plane from the sensor nodes. This study presents SDN-based load-balanced opportunistic-routing for duty-cycled WSNs that addresses two parts. First, the candidates are computed and controlled in the control plane. Second, the metric used to prioritize the candidates considers the average of three distributions, transmission distance distribution, expected number of hops distribution and residual energy distribution so that more traffic is guided through the nodes with higher priority. Simulation results show that our proposed protocol significantly improve network lifetime, routing efficiency, energy consumption, sender waiting time, and duplicate packets as compared with the benchmarks.

Study on Residual Oil Distribution Law during the Depletion Production and Water Flooding Stages in the Fault-Karst Carbonate Reservoirs

The fault-karst carbonate reservoir is a new type of deep carbonate oil and gas resource and a target for exploration and development. The distribution of remaining oil in this kind of oilfield is very complicated because of its unique reservoir characteristics of vertical migration and accumulation, segmented accumulation, and differential accumulation. Therefore, the S91 reservoir block, a typical fracture-vuggy carbonate reservoir in the Tahe oilfield, was taken as the object of this research. According to the development characteristics as well as the porosity and permeability characteristics of the fracture-vuggy, the reservoirs were divided into three types: cave, pore, and fracture. A numerical simulation model of the fracture-vuggy reservoir of the S91 unit was established, and the historical fitting accuracy with dynamic production data was more than 90%. Then, the distribution characteristics of the remaining oil in the depletion stage of the fault-karst carbonate reservoir were further studied and based on the analysis of the reservoir water-flood flow line, the remaining oil distribution characteristics in the depletion stage of the fault solution reservoir were revealed. The results show that the remaining oil distribution patterns during the depletion production stage can be divided into three types: attic type, bottom water coning type, bottom water running type. Due to the serious problem of the bottom aquifer lifting caused by the reservoir development, the residual oil between wells was relatively abundant during the depletion production stage. According to the simulation results, the remaining oil distribution modes in the water drive development stage were identified as three types: sweeping the middle between wells, bottom water connection and circulation, and oil separation through high-permeability channels. In addition, the reservoir connectivity was the main controlling factor for the remaining oil distribution in the fault-karst carbonate reservoir.

An experimental study of CO2 injection strategies for enhanced oil recovery and geological sequestration in a fractured tight sandstone reservoir

Carbon dioxide enhanced oil recovery has been considered and tested in unconventional oil reservoirs due to its additional environmental benefits from simultaneous CO2 geological sequestration. However, it will require a proper injection strategy to overcome unfavorable sweep efficiency in CO2 displacement, which is even magnified in unconventional oil reservoirs due to strong heterogeneity caused by natural and artificial fractures. In this study, we investigated three immiscible CO2 injection strategies at reservoir conditions using tight fractured sandstone cores from the Ordos Basin, China: water alternative gas injection, cyclic CO2 injection, and CO2 foam/surfactant alternative gas injection. A pressurization and miscible CO2 injection were then added after each injection strategy to examine the influence of residual liquid distributions on the miscible displacement efficiency after the tested injection schemes. The core plugs with comparable porosity and permeability were selected, and all cores reached a similar recovery factor (∼11%) after primary CO2 flooding. We found that the cyclic CO2 injection had best performance, with the highest incremental and accumulative oil recovery at 23.6% and 32.26%. Its relatively higher sweep efficiency indicated a uniform CO2 distribution at the end of the cyclic injection, which further led to the highest incremental recovery of 4.94% in the following miscible injection. Comparable CO2 storage capacities were observed in the three fractured core samples (12.21%, 12.98%, and 9.71%, respectively) after completing the miscible displacements. In general, cyclic CO2 injection is recommended as an effective CO2 EOR and geo-storage in tight fractured rocks.

Study on Laser Scan Strategy for Correcting Anisotropic Residual Stress Distribution and Reducing Warpage in Structures Fabricated by PBF-LB/M

Metal-based powder bed fusion with a laser beam (PBF-LB/M) can be applied to fabricate high-accuracy structures compared with other metal additive manufacturing (AM) methods. The rapid solidification of metal powder formed by laser irradiation introduces heterogeneous residual stress, which causes deformation and cracking of the structure. This, in turn, results in the deterioration of quality. In this study, the influence of the laser scan strategy on the residual stress distribution and warpage of the structure was investigated. Using maraging steel powder with an average particle size of 32.5 μm, the structures were constructed using several laser scan strategies at a wavelength of 1070 nm. The residual stress distributions on the surface of the structures were measured by the cosα method by applying X-ray diffraction (XRD). In addition, the warpage of the reverse side of the substrate as a foundation of the structure was measured by a stylus-type surface roughness measuring instrument. The results clarified that the structures constructed by unidirectional scan directions had a tensile residual stress that was generated parallel to the laser scan direction. Meanwhile, the compressive residual stress was generated perpendicular to the laser scan direction. The large warpage was aligned with the laser scan direction and tensile residual stress. When the laser scan direction was rotated by 90° for each layer, the residual stress distribution was generated with a cruciform shape. It was indicated that this residual distribution was caused by a laser scan on the top surface and a lower layer. The anisotropic residual stress distribution and reduction of warpage could be corrected by rotating the laser scan direction by 15° in each layer.

Research on the Application of Var Model in Shanghai Interbank Lending Market

Based on the Shibor data of China's Shanghai Interbank offered rate from May 15, 2017 to May 15, 2022, this paper comprehensively discusses the construction methods of various GARCH family models under different residual difference distribution, and adopts the out-of-sample forecasting method of rolling time window. The forecast value of interest rate volatility under different model assumptions is calculated empirically, and the VaR is calculated based on it. Through empirical research, we draw the following conclusions: (1) t distribution can better describe the distribution of the series of Shanghai Interbank offered rate; (2) The leverage effect of Shanghai Interbank Offered rate series is significant; (3) At present, there are certain interest rate risks in Shanghai inter-bank lending market.

Prediction of chloride ion concentration distribution in basalt-polypropylene fiber reinforced concrete based on optimized machine learning algorithm

The distribution characteristics of chloride ion concentration in basalt-polypropylene fiber reinforced concrete (BPFRC-CC) are important for assessing the durability of concrete structures under marine environment. This study collected the distribution data of BPFRC-CC in three different environments: tidal, submersible, and salt spray. Several optimized machine learning models were developed to predict the distribution of BPFRC-CC. The performance of these models was evaluated based on a comparison between actual and predicted values, residual distribution histograms, and performance indicators. The research results of this article showed that the particle swarm optimization support vector regression (PSO-SVR) model exhibits significant accuracy and generalization ability, with closer proximity to the actual values in both the training and testing sets. The residual distribution histogram of the PSO-SVR model approximated a normal distribution with a smaller mean and standard deviation. Evaluation indicators, including R2, MSE, RMSE, MAE, and MAPE, for the PSO-SVR model were 0.994, 6.92e-5, 0.0083, 0.0062, and 0.0453, respectively. The SHAP values revealed that depth and age were the most critical influencing factors. The decrease in age, water-cement ratio, and water-binder ratio, the addition of basalt fibers and polypropylene fibers, and the increase in depth reduced the BPFRC-CC. In addition, BPFRC-CC in tidal, salt spray, and submersible areas decreased in that order. Finally, a graphical user interface for BPFRC-CC was developed, providing researchers and production personnel with an intuitive, efficient, and visual production experience. This study has important implications for the optimization of BPFRC formulations and the prediction and assessment of the life of BPFRC structures.

Linking Green Infrastructure Deployment Needs and Agroecosystem Conditions for the Improvement of the Natura2000 Network: Preliminary Investigations in W Mediterranean Europe

Reconnecting natural habitats and improving agroecosystem conditions are strategic targets set by several European policies. In order to combine both of these needs, the European Biodiversity Strategy for 2030 has triggered new investments in Green Infrastructure (GI), which actually represents a valuable tool to increase ecological connectivity across natural and semi-natural habitats. In particular, GI may benefit the Natura2000 (N2K) network (i.e., the network of protected sites under the EU Habitats and Birds Directives) by reinforcing the node/site number, extent, and distribution and by improving connections between often small and isolated habitat patches. However, there is a lack of knowledge on what the actual needs of GI deployment are for improving the current N2K network, on the distribution of these needs across Europe and on the potential role of agricultural areas in the improvement of the network functionality. Concurrently, especially in SW Europe, there is an ongoing trend toward the homogenisation and intensification of agricultural systems and the combined loss of associated landscape elements, such as natural and semi-natural Small Woody Features (SWF). Although a well-planned network of such elements could support biodiversity and landscape connectivity, thus effectively complementing the N2K network, little evidence is available on their abundance and residual distribution, especially in agricultural areas and at continental/bioregional scales. Therefore, the present work is aimed at (i) identifying different types of territorial units (NUTS3) in W Mediterranean Europe according to current N2K network features, the overall composition of the actual landscape mosaic and the potential natural heterogeneity of the environment and (ii) identifying and spatialising N2K-related GI deployment needs according to a more specific network analysis in terms of nodes (extent of the total protected area) and links (density of residual woody elements in arable land) within the different types of NUTS3. By means of this wide-scale investigation, four different types of GI deployment needs were generalised across the W Mediterranean Europe NUTS3. Overall, the need for connection restoration prevails, followed by the need for the consolidation of node and link conservation, for the creation of new protected sites and for the enlargement of existing N2K sites. Although useful for a preliminary setting, the shortcomings related to summary data at the European level were also highlighted when compared to local-scale information, with the latter being more suitable for identifying and prioritising truly effective GI conservation and restoration actions.

Rényi Entropy for Past Lifetime Distributions with Application in Inactive Coherent Systems

In parallel with the concept of Rényi entropy for residual lifetime distributions, the Rényi entropy of inactivity time of lifetime distributions belonging to asymmetric distributions is a useful measure of independent interest. For a system that turns out to be inactive in time t, the past entropy is considered as an uncertainty measure for the past lifetime distribution. In this study, we consider a coherent system that includes n components and has the property that all the components of the system have failed at time t. To assess the predictability of the coherent system’s lifetime, we use the system’s signature to determine the Rényi entropy of its past lifetime. We study several analytical results, including expressions, bounds, and order properties for this measure.

Properties of multi-GNSS uncalibrated phase delays with considering satellite systems, receiver types, and network scales

The Wide-Lane (WL) and Narrow-Lane (NL) Uncalibrated Phase Delays (UPDs) are the prerequisites in the traditional Precise Point Positioning (PPP) Ambiguity Resolution (AR). As the generation mechanism of various biases becomes more complex, we systematically studied the impact factors of four satellite systems WL and NL UPDs from the perspective of parameter estimation. Approximately 100 stations in a global network are used to generate the UPDs. The results of different satellite systems show that the estimation method, update frequency, and solution mode need to be treated differently. Two regional networks with different receiver types, JAVAD, and Trimble, are also adopted. The results indicate that the receiver-dependent bias has an influence on UPD estimation. Also, the hardware delays can inhibit the satellite-side UPDs if these receiver-specific errors are not fully deployed or even misused. Furthermore, the temporal stability and residual distribution of NL UPDs are significantly enhanced by utilizing a regional network, with the improvements by over 68% and 40%, respectively. It demonstrates that different network scales exhibit the different implication of unmodeled errors, and the unmodeled errors cannot be ignored and must be handled in UPD estimation.

Microscopic Distribution and Development Strategy of Residual Oil in Tight Sandstone

Pore and permeability are distributed discontinuously and unevenly in the dominant sedimentary model of the lateral accretion body inside the meandering river point bar of the Fuyang reservoir of the Yushulin oilfield. Based on the water flooding experiments of field core samples, the influence of pore permeability conditions on residual oil distribution type and water cutting rate was studied by using the microscopic visualization technology enabled through a photolithographically fabricated glass model. It is found that the residual oil in samples shows five discontinuous types, which are cluster, columnar, oil droplet, membrane, and blind end. In the stages with low, medium, and high water cutting rates, the proportion of clustered residual oil in the samples with different permeability is high, reflecting the situation that it is difficult for injected water to spread widely in tight oil reservoirs. With the decrease of permeability, the proportion of membrane and blind end residual oil gradually increases, which indicates that the thin pore throat can produce large restrictions on residual oil, resulting in residual oil enrichment. At the same time, the water flooding experiment was carried out by changing the displacement direction and periodic water injection. It was found that changing the displacement direction was beneficial to the recovery of residual oil in the thin pore throat and avoided the dominant seepage of injected water in the big pore throat, and the recovery rate was increased by more than 2.14%. Periodic water injection, which was conducive to adjusting the displacement pressure difference, reduced the constraining force of the throat on residual oil and increased the recovery rate by more than 3.98%. The actual well area with closed coring wells and dynamic production data is preferred for the application of experimental research results. Changing displacement direction and periodic water injection increased the residual oil recovery by more than 3%.

Evolution Law of Dominant Flow Channel and Enhanced Oil Recovery Measures for Water Flooding in Reservoirs with Partially Sealed Faults.

The presence of strongly sealed faults can divide a reservoir into complex fault blocks, while partially sealed faults can be created by farewell faults within each block, leading to more intricate fluid migration and residual oil distribution. However, oilfields often overlook these partially sealed faults, focusing instead on the entire fault block, which can impact the efficiency of the production system. In addition, the current technology struggles to quantitatively describe the evolution of the dominant flow channel (DFC) during the water-flooding process, especially in reservoirs with partially sealed faults. This limits the ability to formulate effective enhanced oil recovery measures during the high water cut stage. To address these challenges, a large-scale sand model of a reservoir with a partially sealed fault was designed, and water flooding experiments were conducted. Based on the results of these experiments, a numerical inversion model was established. By combining percolation theory and the physical concept of DFC, a new method was proposed to quantitatively characterize DFC using a standardized flow quantity parameter. The evolution law of DFC was then studied, considering the variations of volume and oil saturation of DFC, and the water control effect of different measures was evaluated. The results revealed that, during the early stage of water flooding, a vertical uniform dominant seepage zone formed near the injector. As the water was injected, DFCs from the top of the injector to the bottom of the producers gradually formed in the unoccluded area. However, DFC was only formed at the bottom in the occluded area. During water flooding, the volume of DFC in each area gradually increased and then tended to stabilize. The development of the DFC in the occluded area lagged behind due to gravity and fault occlusion, leading to the formation of an unswept area near the fault in the unoccluded area. The volume of the DFC in the occluded area was the slowest, and the volume was the smallest after stabilization. Although the volume of the DFC near the fault in the unoccluded area grew the fastest, the volume was only higher than that in the occluded area after stabilization. During the high water cut period, the remaining oil was mainly distributed in the upper part of the occluded area, the area near the unoccluded fault, and the top of the reservoir in other areas. The plugging of the lower part of the producers can increase the volume of DFC in the occluded area, and the DFC moves up throughout the entire reservoir. This improves the utilization degree of the remaining oil at the top of the entire reservoir, but the remaining oil near the fault in the unoccluded area remains inaccessible. The combination of producer conversion, drilling infill wells, and producer plugging can alter the injection-production relationship and weaken the occlusion effect of the fault. The occluded area forms a new DFC, leading to a significant increase in the recovery degree. The deployment of infill wells near the fault in the unoccluded area can effectively control the area and improve the utilization of the remaining oil.

Experimental study on gas-assisted cyclic steam stimulation under heavy-oil sandstone reservoir conditions: Effect of N2/CO2 ratio and foaming agent

After several rounds of cyclic steam stimulation (CSS), the formation energy of heavy oil reservoirs is depleted. The water content in the reservoir is increased, which leads to a decrease in production. The injection of N2 and CO2 can effectively improve the recovery efficiency. In this paper, the experiments of mixed gas-assisted CSS with different N2/CO2 injection ratios and mixed gas foam-assisted CSS were performed. The temperature change, liquid production, pressure change and residual oil distribution of the sandpack were tested during the experiment, and the influencing factors of enhanced oil recovery were explored. The results show that the range of recovery variation can be divided into an increasing phase from 1:0 to 2:1 and a decreasing phase from 2:1 to 0:1 based on the different injection ratios of N2/CO2. The viscosity reduction of heavy oil under the effect of CO2 dissolution is the dominant factor in the increasing phase, while the formation energy increase under the effect of N2 expansion is the dominant factor in the decreasing phase. The recovery factor is the best when the ratio of injected N2/CO2 is 2:1. The cumulative recovery factor increases by 6.46% after adding the A-9 foaming agent solution. This shows that the mixed gas foam combines the advantages of the mixed gas and foam. It increases the flow resistance and improve the oil displacement efficiency by plugging the lager pore-throat from a microscopic perspective. Therefore, mixed gas foam-assisted CSS can effectively improve the production of heavy oil reservoirs. The research results provide theoretical guidance for improving the effectiveness of the CSS of heavy oil reservoirs.

General prediction model of residual pretightening force of bolt group with one-step and multi-step pretightening and analysis of influencing factors from the perspective of elastic interaction

PurposeThe purpose is to predict the distribution of the residual pretightening force of the bolt group under the action of any initial pretightening force, and to achieve the final residual pretightening force as the target to solve the initial pretightening force value to be applied.Design/methodology/approachBased on the finite element method and the elastic interaction theory between bolt group, this paper establishes a prediction model for the residual pretightening force distribution of bolt group for one-step pretightening and multi-step pretightening of gasketless flange connection systems. In addition, using the general modeling method given in this paper, the prediction model of residual pretightening force of long plate bolt connection system is established, and compared with reference, which fully proves the effectiveness and universality of the general prediction model of residual pretightening force of bolt group.FindingsThe appropriate pretightening sequence, increasing the number of pretightening steps and variable amplitude loading can effectively reduce the influence of elastic interaction and improve the uniformity of residual pretightening force of the bolt group. And the selection of material, number of bolts and connected thickness of bolt connection system also has a great influence on the distribution of residual pretightening force of bolt groups.Originality/valueThe general prediction model for the residual pretightening force of bolt group of connecting structural components considering elastic interaction given in this paper can provide a reference for the design and optimization of the bolt assembly process of the rotor system and the casing system in aero-engine and the prediction of the performance of the connecting system.

Identification of the immune-related biomarkers in Behcet’s disease by plasma proteomic analysis

BackgroundThis study aimed to investigate the expression profile of immune response-related proteins of Behcet’s disease (BD) patients and identify potential biomarkers for this disease.MethodsPlasma was collected from BD patients and healthy controls (HC). Immune response-related proteins were measured using the Olink Immune Response Panel. Differentially expressed proteins (DEPs) were used to construct prediction models via five machine learning algorithms: naive Bayes, support vector machine, extreme gradient boosting, random forest, and neural network. The prediction performance of the five models was assessed using the area under the curve (AUC) value, recall (sensitivity), specificity, precision, accuracy, F1 score, and residual distribution. Subtype analysis of BD was performed using the consensus clustering method.ResultsProteomics results showed 43 DEPs between BD patients and HC (P < 0.05). These DEPs were mainly involved in the Toll-like receptor 9 and NF-κB signaling pathways. Five models were constructed using DEPs [interleukin 10 (IL10), Fc receptor like 3 (FCRL3), Mannan-binding lectin serine peptidase 1 (MASP1), NF2, moesin-ezrin-radixin like (MERLIN) tumor suppressor (NF2), FAM3 metabolism regulating signaling molecule B (FAM3B), and O-6-methylguanine-DNA methyltransferase (MGMT)]. Among these models, the neural network model showed the best performance (AUC = 0.856, recall: 0.692, specificity: 0.857, precision: 0.900, accuracy: 0.750, F1 score: 0.783). BD patients were divided into two subtypes according to the consensus clustering method: one with high disease activity in association with higher expression of tripartite motif-containing 5 (TRIM5), SH2 domain-containing 1A (SH2D1A), phosphoinositide-3-kinase adaptor protein 1 (PIK3AP1), hematopoietic cell-specific Lyn substrate 1 (HCLS1), and DNA fragmentation factor subunit alpha (DFFA) and the other with low disease activity in association with higher expression of C–C motif chemokine ligand 11 (CCL11).ConclusionsOur study not only revealed a distinctive immune response-related protein profile for BD but also showed that IL10, FCRL3, MASP1, NF2, FAM3B, and MGMT could serve as potential immune biomarkers for this disease. Additionally, a novel molecular disease classification model was constructed to identify subsets of BD.

Oligo-residual disease in PD-1/PD-L1 inhibitor-treated metastatic non-small cell lung cancer: Incidence, pattern of failure and clinical value of local consolidative therapy.

e21143 Background: Growing numbers of clinical trials are testing the efficacy of incorporating local therapy into programmed death receptor (ligand) 1 (PD-1/PD-L1) inhibitors in metastatic non-small cell lung cancer (NSCLC), but the optimal timing and patient selection are still controversial. We aimed to examine the patterns of maximum tumor response and treatment failure in PD-1/PD-L1 inhibitor-treated NSCLC, and explore the potential clinical value of local consolidative therapy (LCT) in those with oligo-residual disease (ORD). Methods: Metastatic NSCLC treated with PD-1/PD-L1 inhibitors in three academic centers from May 2018 to December 2021 were retrospectively reviewed and those derived clinical benefit, defined as having objective response or durable stable disease lasting≥6months, were finally enrolled. Patterns of tumor response and treatment failure were extensively analyzed. ORD was defined as residual tumor distribution limited to 3 organs and 5 lesions, otherwise was defined as multiple residual disease (MRD). Local therapies targeting the residual tumor lesions performed after PD-1/PD-L1 inhibitors initiation and before initial disease progression, were considered as LCT. The primary endpoints were the overall survival (OS) and progression-free survival (PFS). Results: Of the 318 patients enrolled, ORD and MRD were documented in 122 (38.4%) and 196 (61.6%) patients, respectively. Those who developed ORD had a significantly longer OS than those with MRD (p = 0.006). The median time to best response was 4 months and more than 50% of the initial disease progression developed only from the residual tumor lesions, providing the preliminary rationale of LCT. Among the 122 patients with ORD, those receiving LCT (n = 39) had significantly longer PFS (p = 0.04) and OS (p &lt; 0.001) than those without LCT. Moreover, LCT remained one of the independent predictors of improved PFS and OS after Cox analyses. Conclusions: Local consolidative therapy seems to be feasible and may provide extra survival benefit for metastatic NSCLC patients with oligo-residual disease after PD-1/PD-L1 inhibitor treatment.

Experimental study on fluid flow behaviors of waterflooding fractured-vuggy oil reservoir using two-dimensional visual model

The carbonate reservoir plays a pivotal role in conventional oil and gas reservoirs. However, due to limited knowledge of fluid flow characteristics in fractured-vuggy carbonate formations (vuggy means a small to medium-sized cavity inside rock), high efficiency reservoir development remains challenging. In this study, the similarity principle is utilized to design a two-dimensional visual model based on geological data and the injection-production characteristics of a fractured-vuggy reservoir in M Oilfield. To investigate the characteristics of oil–water flow, the oil–water interface, and residual oil distribution, flooding experiments are conducted at various injection-production positions, types, and injection rates. The results suggest that a low injection/high production strategy is optimal for achieving maximum oil recovery. As a consequence, this configuration is employed in the subsequent flooding experiments. The optimal oil recovery of 82.2% is attained via pore injection and vug production. The Jamin effect exerts an influence on the oil-water flow in structures connected by small channels at the bottom of large vugs, necessitating adjustment of the flow rate to achieve optimal injection conditions. The variation of the oil–water interface height in each vug due to structural flaws results in suboptimal overall oil recovery. The oil recovery is limited to approximately 30% at an injection rate below 8 ml/min but can be enhanced to over 70% with a higher injection rate exceeding 8 ml/min. The residual oil of the fractured-vuggy reservoir is typically found in the tops of structures and peripheral areas with poor connectivity. The findings of this study offer direction for optimal production in fractured-vuggy carbonate reservoirs and facilitate a more comprehensive comprehension of oil–water flows within the reservoir.