Integrated Control Research Articles

Comprehensive Analysis of the Integration and Advanced Control of Photovoltaic Systems for Grid-Connected Applications

In-depth examination of photovoltaic (PV) system integration and enhanced control for grid-connected applications is presented in this study. It examines the difficulties, methods of control, and cutting-edge technologies needed to raise the dependability and effectiveness of PV systems in contemporary power networks. The study explores innovative Maximum Power Point Tracking (MPPT) algorithms, dynamic modeling methodologies, and different adaptive control strategies, emphasizing their importance in PV system performance optimization. It also looks at how high solar PV penetration affects grid stability and talks about creative ways to deal with these issues so that we can have robust and sustainable energy sources in the future. Key Words: photovoltaic Systems, pv integration, pv control strategies, energy storage systems, smart grid technologies, MPPT.

Coordinated Frequency Modulation Control Strategy of Wind Power and Energy Storage Considering Mechanical Load Optimization

When a doubly fed induction generator (DFIG) participates in primary frequency modulation by rotor kinetic energy control, the torque of the generator is changed sharply and the mechanical load pressure of the shaft increases rapidly, which aggravates the fatigue damage of shafting. In order to alleviate the fatigue load of shafting, energy storage was added in the primary frequency modulation of a wind turbine, and a coordinated frequency modulation control strategy of wind power and energy storage based on fuzzy control was proposed. The wind-storage frequency modulation power command was allocated to reduce the response speed of the wind turbine to alleviate the load pressure on the shafting by the fuzzy controller considering the rotor speed range and the state of energy storage charge, and the remaining demand power was supplemented by energy storage. Finally, the joint simulation model based on GH Bladed–Matlab was used to verify the effectiveness of the proposed control strategy. Compared with the traditional integrated control of virtual inertia, the proposed method can reduce the load pressure and fatigue damage of the shafting while satisfying the requirement of frequency modulation.

Control and recalibration of path integration in place cells using optic flow.

Hippocampal place cells are influenced by both self-motion (idiothetic) signals and external sensory landmarks as an animal navigates its environment. To continuously update a position signal on an internal 'cognitive map', the hippocampal system integrates self-motion signals over time, a process that relies on a finely calibrated path integration gain that relates movement in physical space to movement on the cognitive map. It is unclear whether idiothetic cues alone, such as optic flow, exert sufficient influence on the cognitive map to enable recalibration of path integration, or if polarizing position information provided by landmarks is essential for this recalibration. Here, we demonstrate both recalibration of path integration gain and systematic control of place fields by pure optic flow information in freely moving rats. These findings demonstrate that the brain continuously rebalances the influence of conflicting idiothetic cues to fine-tune the neural dynamics of path integration, and that this recalibration process does not require a top-down, unambiguous position signal from landmarks.

Optimizing Length Scalability of InGaZnO Thin‐Film Transistors through Lateral Carrier Profile Engineering and Negative ΔL Extension Structure

AbstractThe lateral carrier profile of amorphous indium gallium zinc oxide (IGZO) thin‐film transistors (TFTs) plays a significant role in determining the effective channel length (Leff) and length scalability even when the physical gate length (Lg) is the same. Especially, devices with high carrier concentration that have a high mobility of 14.54 cm2 V·s−1 suffer from severe short channel effects at Lg = 1 µm due to the reduced Leff. The current work proposes a systematic methodology for optimizing length scalability for a given Lg that involves engineering of the lateral carrier profile. Unique lateral carrier profiles are extracted using contour maps of ΔL and RSD as a function of carrier profile parameters, and they are validated by comparing the measured Leff, drain‐to‐source resistance, and current‐voltage characteristics with the results of simulations using the extracted carrier profiles. Further, to overcome the trade‐off between enhanced mobility and degraded VT roll‐off that occurs with increasing carrier concentration, an IGZO TFT with gate‐insulator shoulders is fabricated to structurally form negative ΔL and physically increase Leff, while also obtaining a high carrier concentration, ultimately achieving both optimal electrical performance, with mobility of 17.50 cm2 V·s−1, and complete control of the electrostatic integrity of the gate.

Estimation of economic losses due to leptospirosis in dairy cattle

There are few studies that effectively quantify the economic losses resulting from problems caused by leptospirosis in naturally infected dairy cattle. Given this gap, the objective of this study was to propose and apply a method to quantify the economic losses resulting from productive and reproductive problems in a commercial dairy herd naturally infected by Leptospira spp. For this study, the zootechnical and economic indicators at a property with Jersey cattle were analyzed during the period from 2014 to 2017. The leptospirosis outbreak occurred in 2014, and the therapeutic approach was carried out between 2015 and 2017, with the latter considered the year of control of the outbreak. The adopted integrated control strategy consisted of dividing the herd according to the serological results obtained through the microscopic agglutination test, the treatment of reagents with streptomycin, and vaccination against leptospirosis of non-reagent heifers and cows. The method used to evaluate the economic indicators of the property was the calculation of the gross margin by taking into account the implicit and explicit cost parameters associated with the manifestation of leptospirosis. The prevalence rate of leptospirosis decreased from 49.4 % in 2015 to 21.6 % in 2017. There was a reduction in the abortion rate (from 40.00 % in 2014 to 9.00 % in 2017), in the stillborn rate (from 2.63 % in 2014 to 1.69 % in 2017) and an increase in the calving rate (from 65.00 % in 2014 to 86.00 % in 2017). In addition, there were increases in the number of lactating cows (from 38 in 2014–57 in 2017) and the mean times of lactation duration, which increased from 275 days in 2014–295 days in 2017. As a result, the average annual production of milk increased from 164,655 liters in 2014–248,521 liters in 2017. In 2014, when treatment hadn’t yet started, the gross margin per liter of milk sold, considering implicit and explicit costs, was US$0.00. In 2015 and 2016, US$0.27 and US$0.30 were obtained, respectively, for this variable. In 2017, with the disease under control on the property, the gross margin per liter of milk reached US$0.36. The gross margin per liter of milk sold was higher in the period when the disease was controlled, showing losses of up to 84 % of the gross margin during the outbreak. Immediate treatment of positive cows and preventive measures had a significant impact on improving the productive and economic efficiency of the property.

Adaptive fuzzy integrated LMS based control strategy for voltage power quality enhancement

In this paper, an adaptive Takagi Sugeno (TS) Fuzzy integrated Mixed Order Normalized Least Mean Square/Fourth Algorithm (MONLMS/F) is proposed for the unresolved voltage power quality issues in distribution system. The proposed control utilizes the cost function of mixed order of errors, which are based on second and fourth order and the feature of cost function overcomes the demerit of traditional basic least mean square method, which is based on second-order error. The implemented control technique has two main objectives. Firstly, the fundamental estimation of correct active and reactive signals from polluted grid voltage for computing the reference load voltages and second is the DC link voltage regulation. A correct weight estimation is achieved by Mixed Order Normalized Least Mean Square/Fourth Algorithm (MONLMS/F) and voltage regulation is performed by Takagi Sugeno Fuzzy (TSF) approach. The proposed integrated control enhances the capability of system against voltage deviation from the reference voltage and successfully eliminates the harmonics from polluted grid voltages. A bio-inspired optimizer like Spotted Hyena (SH) is integrated with TSF for self-tuning of the membership functions (MFs) and fuzzy rule to adapt the system variations and regulate fluctuations in the DC link for dynamic conditions. However, auto-tunned TS-Fuzzy have a fast transient response of DC and AC link voltage based on dynamic indicators like settling time (ts=0.12 s), undershoot (Us=3.4 %) and peak overshoot (Mp=5.6 %) are compared to classical PI controller. Nonetheless, the proposed TS-MONLMS/F control strategy outperforms the other classical control with low oscillations at any power quality scenario with improved dynamic response. The significant MATLAB simulation and experimental results are evaluated, and its performance is demonstrated with the dSPACE (DS1202) processor for experimental realization.

Comparison of deviceless methods for distant object manipulation in mixed reality

Mixed Reality (MR) applications based on the current generation of Head-mounted displays (HMDs) support a deviceless manipulation of virtual objects based on finger tracking and control of the 3D transformation with gestures. However, when the object manipulation is performed at some distance, and when the transform includes scaling, it is not apparent how to remap the hand motions over the degrees of freedom of the object. The most popular software toolkits used for XR development provide specific solutions, but there are still usability issues and a need for clear guidelines for the interaction design.In this work, we compare three different solutions for the devices and remote translation, rotation, and scaling of virtual objects in a real environment in two user studies aimed at assessing the usability of the methods for different tasks. The tasks are a fast and rough docking of virtual cubes on a tangible shelf from varying distances and the accurate placement of cubes on the shelf in a fixed amount of time.The outcomes of these studies show that the usability of the manipulation methods is strongly affected by the use of separate or integrated control of the degrees of freedom, by the use of the hands in a symmetric or specialized way, by the visual feedback, and by the previous experience of the users and provides valuable guidelines for the design of interactive mixed environments.

Modeling the dynamics of Onchocerca volvulus with the impact of environmental factors on blackfly breeding sites

Onchocerciasis is a significant public health concern, characterized by infections affecting the eyes and skin. The environmental factors contributing to its widespread occurrence are frequently undervalued, despite their significant influence. This research introduces an innovative mathematical model that utilizes fractional derivatives to examine the impact of several important variables, including temperature, river velocity, and oxygen concentration, on the breeding locations of blackflies. The objective of our study is to improve comprehension regarding the influence of environmental elements on the dynamics of onchocerciasis transmission. The efficacy of multiple vector control tactics and host screening approaches, such as skin snip biopsy and continuous detection at healthcare facilities, is evaluated through a series of comprehensive numerical experiments. Our results highlights the potential effectiveness of implementing comprehensive vector management strategies, in conjunction with frequent host screening techniques, in substantially decreasing the rates of disease transmission. Our study specifically emphasizes the efficacy of these interventions in riverine environments that are characterized by varying environmental circumstances. The findings obtained from this study have important significance for the development and execution of focused public health interventions aimed at combating onchocerciasis in areas where environmental factors are crucial in the transmission dynamics of the illness. This study provides significant insights into the worldwide endeavor to combat neglected tropical diseases, highlighting the critical importance of environmental factors and implementing integrated control techniques for efficient disease management and prevention.

Improving stability and adaptability of automotive electric steering systems based on a novel optimal integrated algorithm

PurposeDesign a novel optimal integrated control algorithm for the automotive electric steering system to improve the stability and adaptation of the system.Design/methodology/approachSimulation and calculation.FindingsThe output signals follow the reference signal with high accuracy.Originality/valueThe optimal integrated algorithm is established based on the combination of PID and SMC. The parameters of the PID controller are adjusted using a fuzzy algorithm. The optimal range of adjustment values is determined using a genetic algorithm.

Helminthiasis and malaria co-infection among women of reproductive age in a rural setting of Kilifi County, coastal Kenya: A mixed method study.

Soil transmitted helminthiasis (STH), Schistosoma haematobium and malaria co-infection lead to increased susceptibility to other infections and poor pregnancy outcomes among women of reproductive age (WRA). This study sought to establish risk factors, burden of co-infection with STH, S. haematobium and Plasmodium sp. among WRA in Kilifi County, Kenya.A mixed method cross-sectional study was conducted on 474 WRA in 2021. Simple random sampling was used to select WRA from four villages in two purposively sampled sub-counties. Study participants were interviewed, and stool samples collected and analysed using Kato-Katz technique for STH. Urine samples were collected for examination of S. haematobium while malaria microscopic test was done using finger prick blood samples. Further, 15 focus group discussions (FGDs) were conducted with purposively selected WRA and qualitative data analyzed thematically using Nvivo software. Quantitative and qualitative methods were triangulated to comprehensively strengthen the study findings. Prevalence of S. haematobium was 22.3% (95%CI: 13.5-36.9), any STH 5.2% (95%CI: 1.9-14.3) and malaria 8.3% (95%: 3.8-18.2). Co-infections between any STH and S. haematobium was 0.8% (95%CI: 0.2-3.2) and between S. haematobium and malaria 0.8% (95%CI: 0.2-3.1). Multivariable analysis showed increased odds of any STH infections among participants in Rabai Sub-County, (aOR = 9.74; p = 0.026), businesswomen (aOR = 5.25; p<0.001), housewives (aOR = 2.78; p = 0.003), and casual laborers (aOR = 27.03; p<0.001). Qualitative analysis showed that the three parasitic diseases were common and responsible for possible causes of low birth weight, susceptibility to other infections and complications such as infertility and cancer later in life.The study demonstrated that STH, S. haematobium and malaria are still a public health problem to WRA. Some of the associated risks of infection were geographical location, socio-economic and WASH factors. Hence the need to implement integrated control efforts of the three parasitic infection.

A critical review on bacterial black spot of mango caused by Xanthomonas citri pv. mangiferaeindicae: Current status and direction for future research

AbstractBacterial black spot (BBS) of mango, caused by the bacterium Xanthomonas citri pv. mangiferaeindicae, is an emerging disease affecting mango‐producing areas in Asia, Africa, Oceania, and the Americas. The disease spreads primarily through wind‐driven rain and farm implements, and its host range is limited, affecting mango, cashew, and pepper plants. BBS is characterized by dark, angular lesions with elevated borders on infected leaves and fruits in the lower and upper parts of the tree canopy. Infected plants display numerous tiny water‐soaked black lesions on leaves, fruits, and stems. Early symptoms on leaves include tiny, veined, water‐soaked patches with angular black dots and occasionally chlorotic spots. Managing BBS presents challenges, but various control measures have shown effectiveness in different regions. Integrated disease control measures, such as cultural methods and removing diseased plant parts, could further reduce BBS prevalence in the field. This paper reviews the detrimental effects associated with the disease, while also offering a concise overview of the existing body of research concerning BBS and its implications for mango cultivation.

Enhancing grid stability through predictive control and fuzzy neural networks in flywheel energy storage systems integration

Renewable energy systems, exemplified by solar and wind power, are increasingly integrated into modern power grids to mitigate environmental impact and reduce reliance on fossil fuels. However, the inherent intermittency and unpredictability of renewable energy sources pose challenges to grid stability and reliability. Energy Storage Systems (ESS) offer a promising solution to address these challenges by smoothing out power fluctuations and ensuring a consistent power supply. Among various ESS technologies, Flywheel Energy Storage Systems (FESS) have emerged as a noteworthy contender due to their rapid response times, low operating costs, and extended lifespan. This paper focuses on investigating the operation of a novel unit comprising a solar power system integrated with a Flywheel Energy Storage System (PV-FESS). The aim is to develop an effective control algorithm utilizing adaptive fuzzy neural networks and model predictive control (ANFIS-MPC) to manage power fluctuations stemming from renewable energy sources within the grid. The proposed control strategy aims to optimize the operation of the PV-FESS system by dynamically adjusting the energy absorption or release of the flywheel to maintain grid stability. Simulation studies conducted using Matlab-Simulink/Simcape software validate the efficacy of the ANFIS-MPC algorithm in mitigating abnormal fluctuations from renewable energy sources. The results demonstrate that the PV-FESS system effectively balances power fluctuations, ensuring a stable and reliable power output to the grid.

Applying the Integral Controllability Property in a Multi-Loop Control for Stable Voltage Regulation in an Active Distribution Network

Distributed Energies Resources (DERs) can be controlled for supporting the voltage regulation at nodes of an Active Distribution Network (ADN) where they are connected. However, since the ADN is a Multi-Input Multi-Output (MIMO) system with coupled dynamics, the controller of a DER mutually interacts with all other controllers through the distribution lines. These interactions lead to operating conflicts which may drive the ADN to work close to its voltage stability boundaries. To achieve a stable voltage regulation without new investment in the existing ADNs, the present paper proposes a straightforward decentralized design of the multi-loop controllers based on the property of integral controllability. The main feature of the method is that the design problem can be expressed by a single parameter designed both for reducing the effects of the undesired coupling and for increasing the degree of robust stability in the presence of parameter uncertainty in the matrix plant. Simulation studies are developed to illustrate the design result and the performance achieved under different operating conditions. The performance is also compared with the one obtained by another method in terms of the integral absolute error.

Enhancing thermal performance of cylindrical Li-ion battery packs: A 3D simulation with strategic phase change material integration and airflow control

This study conducts a three-dimensional simulation of the temperature of a cylindrical Li-ion battery (LIB) pack with nine cells. The cells are arranged in the pack in square and diamond configurations, and the pack is filled with phase-change materials (PCMs). The airflow enters the channel from two inlets at 90° with respect to the pack and is guided by two blades at the sides of the inlet toward the pack. Arc-shaped and linear blades were used for this study, which was carried out for 2500 s. The results indicate that the square arrangement of batteries, combined with the use of curved blades, has been more effective in reducing temperature. In this configuration, a more uniform distribution of air flow and better efficiency of the PCM in absorbing heat were observed, leading to a significant decrease in the overall temperature of the battery pack. Specifically, compared to the diamond arrangement, the temperature of the batteries in the square arrangement was up to 10 °C lower. This reduction in temperature plays an important role in enhancing the lifespan and safety of the batteries. By using machine learning and providing the optimal model for the maximum temperature of the battery surface, it was shown that this parameter was designed with the model and comparing it with the numerical results had an error of 2.01 %.

Design and Development of Self Balancing Two Wheeler

The Self-balancing robots represent a fascinating intersection of technology and practical application. This project aims to design and develop a self-balancing two- wheeler robot capable of maintaining stability and balance autonomously. Drawing inspiration from principles observed in human balance and locomotion, the robot employs a combination of sensors, actuators, and control algorithms to achieve its objective. The project begins with an in-depth literature survey, exploring existing research and methodologies in the field of self-balancing robotics. Leveraging insights from key publications, the project outlines fundamental principles, sensor fusion techniques, advanced control methodologies, and challenges inherent in self-balancing robot design. Key components including an Arduino Uno board, accelerometers, gyroscopes, DC motors, batteries, and optional reaction wheels are carefully selected and integrated into the robot's hardware architecture. A systematic approach to hardware selection, assembly, sensor integration, microcontroller programming, and motor control ensures a coherent and functional design. Throughout the development process, emphasis is placed on rigorous testing, calibration, and iterative improvement. The robot is subjected to various environmental conditions and scenarios to validate its stability and performance. Calibration procedures refine sensor accuracy and control algorithms, enhancing the robot's ability to maintain balance under dynamic conditions. The project culminates in the creation of a comprehensive documentation package, detailing schematics, code explanations, assembly instructions, and testing methodologies. Additionally, a presentation showcases the robot's functionality, design rationale, and potential applications. By meticulously following the outlined steps and leveraging insights from existing research, this project aims to contribute to the advancement of self-balancing robotics and serve as a foundation for future exploration and innovation in this exciting field

Genotoxicity Associated with Retroviral CAR Transduction of ATM-Deficient T Cells.

Somatic variants in DNA damage response genes such as ATM are widespread in hematologic malignancies. ATM protein is essential for double-strand DNA break repair. Germline ATM deficiencies underlie ataxia-telangiectasia (A-T), a disease manifested by radiosensitivity, immunodeficiency, and predisposition to lymphoid malignancies. Patients with A-T diagnosed with malignancies have poor tolerance to chemotherapy or radiation. In this study, we investigated chimeric antigen receptor (CAR) T cells using primary T cells from patients with A-T (ATM-/-), heterozygote donors (ATM+/-), and healthy donors. ATM-/- T cells proliferate and can be successfully transduced with CARs, though functional impairment of ATM-/- CAR T-cells was observed. Retroviral transduction of the CAR in ATM-/- T cells resulted in high rates of chromosomal lesions at CAR insertion sites, as confirmed by next-generation long-read sequencing. This work suggests that ATM is essential to preserve genome integrity of CAR T-cells during retroviral manufacturing, and its lack poses a risk of chromosomal translocations and potential leukemogenicity. Significance: CAR T-cells are clinically approved genetically modified cells, but the control of genome integrity remains largely uncharacterized. This study demonstrates that ATM deficiency marginally impairs CAR T-cell function and results in high rates of chromosomal aberrations after retroviral transduction, which may be of concern in patients with DNA repair deficiencies.

Health workers' perspectives on school-based mass drug administration control programs for soil-transmitted helminthiasis and schistosomiasis in Ogun State, Nigeria.

Soil-transmitted helminthiasis (STH) and schistosomiasis (SCH) are among the most prevalent neglected tropical diseases (NTDs), affecting 1.5 billion globally, with a significant burden in sub-Saharan Africa, particularly Nigeria. These diseases impair health and contribute to socio-economic challenges, especially in children, undermining educational and future economic prospects. The 2030 NTD Roadmap highlights Mass Drug Administration (MDA) as a critical strategy for controlling these NTDs, targeting vulnerable populations like school-age children. Despite some successes, challenges persist, indicating the need for deeper insights into program implementation. This study focuses on the perspectives of health workers implementing MDA in selected local government areas (LGAs) of Ogun State, Nigeria, aiming to identify challenges and enablers that align with the broader NTD 2030 goals. The study used a qualitative research approach involving focus group discussions and in-depth interviews with health workers engaged in neglected tropical disease control programs in Ogun State, Nigeria, between July and September 2022. A semi-structured questionnaire guided the exploration of ideas, and the data were analyzed using the QRS Nvivo 12 software package. The study found that the school-based MDA control program's efficacy largely relies on strong collaborations and partnerships, particularly with educators, community heads, and other stakeholders. These alliances and strategic communication methods, like town announcements and media campaigns, have been pivotal in reaching communities. However, the program does grapple with hurdles such as parental misconceptions, limited funds, insufficient staffing, and misalignment with the Ministry of Education. It is recommended to boost funding, foster early stakeholder involvement, enhance mobilization techniques, and consider introducing a monitoring card system similar to immunization. The MDA Integrated Control Programs for STH and SCH in Ogun State schools demonstrate a holistic approach, integrating knowledge, collaboration, communication, and feedback. Health workers have shown commitment and adeptness in their roles. However, achieving maximum efficacy requires addressing critical barriers, such as parental misconceptions and funding challenges. Adopting the recommended strategies, including proactive communication, increased remuneration, and introducing a tracking system, can significantly enhance the program's reach and impact. The involvement of all stakeholders, from health workers to community leaders and parents, is essential for the program's sustainability and success.

Sensory integration and segmental control of posture during pregnancy

BackgroundApproximately 25% of pregnant people fall, yet the underlying mechanisms of this increased fall-risk remain unclear. Prior studies examining pregnancy and balance have utilized center of pressure analyses and reported mixed results. The purpose of this study was to examine sensory and segmental contributions to postural control throughout pregnancy using accelerometer-based measures of sway. MethodsThirty pregnant people (first trimester: n = 10, second trimester: n = 10, third trimester: n = 10) and 10 healthy, nonpregnant control people stood quietly for one minute in four conditions: eyes open on a firm surface, eyes closed on a firm surface, eyes open on a foam pad, and eyes closed on foam. Postural sway was quantified using the root mean square accelerations in the anterior-posterior and medial-lateral directions from an inertial sensor at the lumbar region. Sensory sway ratios, segmental coherence and co-phase, were calculated to assess sensory contributions and segmental control, respectively. FindingsPregnant people did not display greater sway compared to healthy, nonpregnant controls. There were no group differences in vestibular, visual, or somatosensory sway ratios, and no significant differences in balance control strategies between pregnant and nonpregnant participants across sensory conditions. InterpretationThe small effects observed here contrast prior studies and suggest larger, definitive studies are needed to assess the effect of pregnancy on postural control. This study serves as a preliminary exploration of pregnant sensory and segmental postural control and highlights the need for future to hone the role of balance in fall risk during pregnancy.

Multi-level prediction of substance use: Interaction of white matter integrity, resting-state connectivity and inhibitory control measured repeatedly in every-day life.

Substance use disorders are characterized by inhibition deficits related to disrupted connectivity in white matter pathways, leading via interaction to difficulties in resisting substance use. By combining neuroimaging with smartphone-based ecological momentary assessment (EMA), we questioned how biomarkers moderate inhibition deficits to predict use. Thus, we aimed to assess white matter integrity interaction with everyday inhibition deficits and related resting-state network connectivity to identify multi-dimensional predictors of substance use. Thirty-eight patients treated for alcohol, cannabis or tobacco use disorder completed 1 week of EMA to report substance use five times and complete Stroop inhibition testing twice daily. Before EMA tracking, participants underwent resting state functional MRIand diffusion tensor imaging (DTI) scanning. Regression analyses were conducted between mean Stroop performances and whole-brain fractional anisotropy (FA) in white matter. Moderation testing was conducted between mean FA within significant clusters as moderator and the link between momentary Stroop performance and use as outcome. Predictions between FA and resting-state connectivity strength in known inhibition-related networks were assessed using mixed modelling. Higher FA values in the anterior corpus callosum and bilateral anterior corona radiata predicted higher mean Stroop performance during the EMA week and stronger functional connectivity in occipital-frontal-cerebellar regions. Integrity in these regions moderated the link between inhibitory control and substance use, whereby stronger inhibition was predictive of the lowest probability of use for the highest FA values. In conclusion, compromised white matter structural integrity in anterior brain systems appears to underlie impairment in inhibitory control functional networks and compromised ability to refrain from substance use.

Failure evaluation mechanism of cement sheath sealing integrity under casing eccentricity during multistage fracturing

A microannulus (MA) is the primary reason for sustained casing pressure in multi-stage fractured-shale gas wells. However, the effect of the casing eccentricity on the long horizontal section has not been considered. In this study, a full-scale integrity tester for cement sheaths is adopted to measure the cumulative plastic deformation. Numerical models are applied to evaluate the development of the cumulative plastic deformation and quantify the MA width considering casing centralization and eccentricity in the context of multiple loading and unloading cycles. Subsequently, the influences of the eccentricity distance and angle, cement-sheath mechanical variables, and different well depths on the cumulative sheath plastic deformation and sheath MA development are explored. The research results demonstrate that casing eccentricity significantly increases the cumulative sheath plastic deformation compared with that of the casing-centered condition. Consequently, the risk of sealing integrity failure increases. The accumulated plastic deformation increases when the eccentricity distance increases. In contrast, the initial plastic deformation increases as the eccentricity angle increases. However, the cumulative plastic deformation decreases after a specific loading and unloading cycle count. Affected by the coupled influence of the internal casing pressure and fracturing stages, the width of the MA in the horizontal section increased from the toe to the heel, and the casing eccentricity significantly increased the MA width at each stage, thus increasing the risk of gas channeling. Finally, an engineering case is considered to study the influence of casing eccentricity. The results show that cement slurries that form low and high elastic moduli can be applied to form a cement sheath when the fracturing stage is lower or higher than a specific value, respectively. The results of this study offer theoretical references and engineering support for the integrity control of cement sheath sealing.