Stabilization Technique Research Articles

Dynamic and modal analysis of nearly incompressible structures with stabilised displacement-volumetric strain formulations

This paper presents a dynamic formulation for the simulation of nearly incompressible structures using a mixed finite element method with equal-order interpolation pairs. Specifically, the nodal unknowns are the displacement and the volumetric strain component, something that makes possible the reconstruction of the complete stain at the integration point level and thus enables the use of strain-driven constitutive laws. Furthermore, we also discuss the resulting eigenvalue problem and how it can be applied for the modal analysis of linear elastic solids. The article puts special emphasis on the stabilisation technique used, which becomes crucial in the resolution of the generalised eigenvalue problem. In particular, we prove that using a variational multiscale method assuming the sub-grid scales to lie in the finite element space orthogonal to that of the approximation, namely the Orthogonal Sub-Grid Scales (OSGS), results in a convenient linear and symmetric generalised eigenvalue problem. The correctness, convergence and performance of the method are proven by solving a series of two- and three-dimensional examples.

Management Options for Traumatic Posterior Sternoclavicular Joint Dislocation: A Narrative Review with a Single Institution's Experience.

Background: Posterior sternoclavicular joint (SCJ) dislocations are rare events that can evolve into real emergencies due to the vital structures in the mediastinum. When closed reduction maneuvers fail, open SCJ reconstruction becomes mandatory, with literature proposing several stabilization techniques that either preserve or remove the SCJ's mobility. This study is a narrative review of the most recent literature regarding posterior trauma to the SCJ along with a single institution's experience of this pathology, managed either conservatively or surgically, with a figure-of-eight autologous semitendinosus graft in case of closed reduction failure. Methods: This article provides an overview of posterior traumatic SCJ dislocation, and it describes five cases of patients managed for traumatic posterior SCJ dislocation treated either conservatively or surgically with a figure-of-eight semitendinosus tendon autograft reinforced with high-strength suture tape. A comparison with the most recent literature is performed, focusing on biomechanics. Results: The demographics, the mechanism of injury, the management algorithm and the surgical strategy align with the most recent literature. Despite the final treatment, at one year of follow-up, the ROM was restored with full strength throughout the range of motion of the shoulder with no neurological deficits. The reduced joint successfully healed in imaging, and patients returned to their daily lives. The surgical site wounds and donor harvest sites were perfectly healed. Conclusions: Although recent recommendations for treating posterior traumatic SCJ dislocation have advanced, no universally accepted method of stabilization exists, and the surgical strategy is generally entrusted to the surgeon's experience. The literature still increasingly supports figure-of-eight ligament reconstruction with a biological or synthetic graft. This work further implements the literature by reporting good outcomes at follow-up.

Slope stability analysis of colluvial deposits along the Muketuri-Alem Ketema Road, Northern Ethiopia

Slope failures are a significant natural geohazard in hilly and mountainous regions, often resulting in loss of life and infrastructure damage. The Muketuri-Alem Ketema road in Ethiopia is particularly vulnerable to landslides due to colluvial deposits on steep slopes from the higher northeastern plots to the lower Jemma River valley. This study investigates the characteristics of colluvial soil and evaluates the stability of slopes prone to landslides. It combines geophysical data, penetrometer tests, laboratory analyses, Google Earth images, and detailed field visits to assess the soil and bedrock composition and structure. Numerical methods, including limit equilibrium (Bishop, Janbu, Spencer, and Morgenstern-Price methods) and finite element methods, were used to analyze slope sections under various saturation conditions and simulate different rainfall patterns. The results indicate that the Bishop, Morgenstern-Price, and Spencer methods produce similar safety factors with minimal differences (<0.3%), while the Janbu method shows more significant variation (1.5%–5.6%). Safety factor differences for sections A-A and B-B range from 5.26% to 9.86% and 3.5%–4.7%, respectively. Simulations reveal that short-term saturation significantly reduces the stability of the upper slope layer by 20%–46.76%, and long-term saturation decreases the entire slope section by 26.81%–46.76% compared to dry conditions due to increased pore water pressure and self-weight. Long-term saturation effects, combined with dynamic loads, can further reduce colluvial soil stability by over 50% compared to a dry static state. The finite element method predicts larger failure zones than limit equilibrium methods, emphasizing the need for accurate predictions to characterize slope behavior during failure and inform stabilization decisions. This study provides crucial data for maintaining and planning the Muketuri-Alem Ketema Road, highlighting slope performance over time and the effectiveness of stabilization techniques.

Assessing river bank erosion on Majuli Island for strength and stability in resilient protection

ABSTRACT The present study addresses the issues and challenges of Brahmaputra river bank erosion near Majuli Island, Assam. For field study, the most vulnerable locations, namely (i) Ahatguri area, (ii) Okhala Chuk, (iii) Kamalabari ferry ghat, (iv) Cinnatoli Chapori and (v) Kandhulimari area are taken into consideration. Geometrical as well as geotechnical investigations were carried out to obtain detailed information for the stability analysis of river bank slopes of selected sites. Through 2-D finite element-based numerical tool PLAXIS2D, results indicated low stability of river bank due to low shear strength and ingress of moisture. To improve the strength and stiffness of the river bank soil, authors suggest a soil stabilisation technique using a Cement-Soil mixture with a 1:25 ratio (4%). The influence of improvement in the geotechnical properties was noted with the improvement in the stability of the river bank soil when assessed numerically. Results depicted that under ‘saturated and stabilized condition’, approximately 99% reduction in maximum total displacement and 55–85% reduction in maximum total strain was observed at all the five critical locations studied. Factor of safety values of stabilised bank was increased by 4.5 to 12 times, compared to the corresponding results obtained for ‘saturated and unstabilized’ condition.

Enhanced stability in Co0.8Ni0.2/NDMCS catalysts: Carbon nitride encapsulation for robust hydrogen generation

Catalytic hydrolysis of NaBH4 is a promising method for "on-demand" hydrogen generation, with cobalt catalysts playing a key role due to their high hydrogen generation rates. However, rapid cobalt dissolution and poor recycling hinder stable hydrogen production. This study presents a dual-mode stabilization technique using carbon nitride encapsulation to address these challenges. Co0.8Ni0.2 alloy nanoparticles (NPs) are confined within N-doped mesoporous carbon spheres (NDMCS) and encapsulated with a carbon nitride shell (∼ 5 nm thick). XPS results reveal strong non-classical metal-support interaction, increasing activation energy from 38.82 to 44.6 kJ mol−1, which controls cobalt's reactivity, leading to excellent recycling efficiency (90 % retention of initial rate, no change in particle size) in high-concentration reactants (2 %NaBH4 + 2 %NaOH). The retention rate drops to 26.8 % without this stabilization due to rapid metal dissolution. This stability of Co0.8Ni0.2 alloy in alkaline conditions has significant practical implications for hydrogen generation and other electrochemical applications.

Three-Dimensional Spectral Element Method Implementation for Evaluating Rooted Soil Behavior in Slope Stability Analysis

Bioengineering techniques are being increasingly adopted as a sustainable solution to soil slope instability. Despite their recognized benefits, however, the mechanistic contribution of vegetation to slope stability remains inadequately understood due to the intricate nature of soil–root interactions and the complexity of root architectures. Most existing research predominantly offers qualitative assessments of vegetation effectiveness. This study aims to numerically substantiate the role of vegetation as a bioengineering technique for soil slope stabilization. Various plant species used commonly for soil stabilization were identified, and undisturbed soil samples were collected to quantify the shear strength parameters of the soils from both barren and vegetated slopes, along with root tensile strengths. A comprehensive topographic survey was conducted to capture the precise topography of the study area. Utilizing these primary data, in this work we develop 3D models for five representative plants within each species category and employ the Spectral Element Method (SEM), an advanced higher-order formulation of the finite element method (FEM), within the 3D domain to evaluate the factor of safety for the soil slopes. The SEM offers superior accuracy and stability in numerical computations. The results obtained through the SEM were corroborated through the FEM modeling and were found to be consistent with other established methodologies. This innovative approach of 3D SEM aims to quantitatively assess the impact of vegetation on soil slope stability and provide a more rigorous understanding of bioengineering applications in geotechnical engineering.

Biomechanical evaluation of an experimental internal ring fixator (RingFix) for stabilization of pelvic ring injuries on an osteoporotic bone model

During the last decades, effective pain reduction and early mobilization were identified as the central priorities in therapy of insufficiency fractures of the pelvis. For operative treatment minimally-invasive stabilization techniques are favored. While there is consensus on the significance of sufficient dorsal stabilization the role of additional fixation of the anterior fracture component stays under discussion. Within the present study we developed an internal ring fixator system (RingFix) with the question whether an in-itself-closed construct can improve stability of the entire ring structure. RingFix was evaluated on an osteoporotic bone model with a standardized FFP IIIc fracture within an established biomechanical setup regarding its primary stabilization potential. Further, it was compared to transiliac–transsacral screw fixation with and without stabilization of the anterior fracture component. The transiliac–transsacral fixation with separate screw fixation of the anterior fracture showed significantly higher stability than the RingFix and the transiliac–transsacral screw fixation without anterior stabilization. Our results show that stabilization of the anterior fracture component relevantly improves the stability of the entire ring construct. As a bridging stabilizer, RingFix shows biomechanical advantages over an isolated dorsal fracture fixation, but inferior results than direct stabilization of the single fracture components.

Environmental Sustainability of Pile Construction Activities in Nigeria; Strategies and Best Practices

: Pile construction activities is a multifaceted activity among the construction activities that are performed by heavy machines, materials and energy sources generating environmental impacts associated with pilling activities such as carbon emissions, noise, heavy vibration, soil instability and groundwater pollution. Sustainable piling construction guarantees that the whole piling process meets environmental sustainability and ultimately human health and wellbeing. Data were gathered through a questionnaire survey administered to construction professionals including engineers, project managers, surveyors, and builders. Out of the 50 questionnaires distributed, 41 responses were analyzed. The study employed the Relative Importance Index (RII) to rank the effectiveness of various strategies in mitigating environmental impacts. The findings underscore the critical role of introducing low-emission machinery and optimizing operational hours in reducing carbon emissions. Noise management was most effectively achieved through alternative pile installation methods combined with regular equipment maintenance. Maintaining adequate setbacks from structures and employing controlled installation techniques were identified as essential strategies to mitigate vibration. Addressing soil instability was found to rely heavily on thorough site investigations and the implementation of effective ground stabilization techniques and preventing groundwater pollution requires the proper use of drilling fluids and diligent site management. These findings contributed to the development of environmentally sustainable practices in pile construction, emphasizing the importance of comprehensive strategies to mitigate the adverse environmental impacts of such activities in Nigeria.

Changes in therapists’ knowledge of symptom management and stabilization following program co-participation with dissociative patients

Few professionals in the mental health field receive systematic training in treating trauma-related symptoms and disorders, including dissociative disorders (DD). Experts in the field of treating DDs recommend building stabilization skills early in treatment to improve emotion regulation and safety, yet research on DD therapists’ actual practices suggest that they are engaging in these practices less than recommended. DD patients may benefit from therapists learning more about emotion regulation and trauma symptom management towards stabilizing difficult experiences and risky, unhealthy, or unsafe behaviors. The current study considered whether an international group of therapists who participated alongside their DD patients in a 2-year Internet-based psychoeducational program demonstrated changes in knowledge related to symptom management and stabilization techniques. Therapists answered five free-form text questions related to DD symptom management and stabilization at baseline, mid-point, and end of the study. Results showed that significant changes in therapist knowledge were evident between baseline and mid-point, as well as between the baseline and the end of the study, with effect sizes ranging from small to large. Compared to when they began the study, therapists were better able to understand their DD patients’ reasons for self-injury, recognize warning signs of unsafe behaviors, identify coping skills, and identify skills to manage overwhelming feelings and intrusive traumatic content. Implications and opportunities for future research are discussed.

Peran Kekuatan Perut dalam Meningkatkan Performa Tolak Peluru pada Atlet

The aim of this research is to determine the role of abdominal strength in improving shot put performance in athletes. This research uses a literature review method by collecting information by looking for relevant references and facts from journals and theses that have been previously researched. The literature is then compared and linked to provide an overview of the topic under study. Qualitative research is used as a type of research. This research explores the role of abdominal muscle strength in improving shot put performance in athletes. Shot put requires the right combination of strength, technique and coordination to achieve optimal results. One key element that is often overlooked is abdominal muscle strength or core strength. This research outlines how abdominal muscle strength contributes to body stability, efficient energy transfer, and optimization of shot put technique. Through literature analysis and research findings, it was concluded that integrated abdominal strength training in athlete training programs can help improve shot put performance by optimizing stability, energy transfer and movement technique. The practical implication is the importance of including abdominal strength training in the training program to achieve maximum performance in shot put and reduce the risk of injury. Further research could explore more deeply the long-term influence of abdominal strength training on the performance of shot put athletes.

Advancements in Phase Change Materials: Stabilization Techniques and Applications

Phase Change Materials (PCMs) are innovative materials that absorb and release thermal energy during phase transitions, making them ideal for thermal energy storage applications. This paper provides a comprehensive overview of PCMs, focusing on their functioning mechanisms, classifications, and shape stabilization methods. PCMs operate by storing latent heat during melting and releasing it upon solidification, thereby maintaining a stable temperature during phase changes. They are classified into three main categories: organic, inorganic, and eutectic. Organic PCMs, such as paraffins and fatty acids, offer high latent heat storage but suffer from low thermal conductivity. Inorganic PCMs, including salt hydrates and metals, provide better thermal conductivity but face challenges like supercooling and corrosiveness. Eutectic PCMs, which are mixtures of compounds, offer customizable melting points and enhanced thermal properties. To address leakage and improve thermal conductivity, shape stabilization methods are employed, such as encapsulation, stabilization by porous matrix, and polymer hybridized shape stabilization. These techniques enhance the structural integrity and thermal performance of PCMs, making them more suitable for practical applications. The paper highlights the potential of PCMs to improve energy efficiency and outlines future research directions for optimizing their performance in various industries.

An Ultra-Low-Voltage Transconductance Stable and Enhanced OTA for ECG Signal Processing.

In this paper, a rail-to-rail transconductance stable and enhanced ultra-low-voltage operational transconductance amplifier (OTA) is proposed for electrocardiogram (ECG) signal processing. The variation regularity of the bulk transconductance of pMOS and nMOS transistors and the cancellation mechanism of two types of transconductance variations are revealed. On this basis, a transconductance stabilization and enhancement technique is proposed. By using the "current-reused and transconductance-boosted complementary bulk-driven pseudo-differential pairs" structure, the bulk-driven pseudo-differential pair during the input common-mode range (ICMR) is stabilized and enhanced. The proposed OTA based on this technology is simulated using the TSMC 0.18 μm process in a Cadence environment. The proposed OTA consumes a power below 30 nW at a 0.4 V voltage supply with a DC gain of 54.9 dB and a gain-bandwidth product (GBW) of 14.4 kHz under a 15 pF capacitance load. The OTA has a high small signal figure-of-merit (FoM) of 7410 and excellent common-mode voltage (VCM) stability, with a transconductance variation of about 1.35%. Based on a current-scaling version of the proposed OTA, an OTA-C low-pass filter (LPF) for ECG signal processing with VCM stability is built and simulated. With a -3 dB bandwidth of 250 Hz and a power consumption of 20.23 nW, the filter achieves a FoM of 3.41 × 10-13, demonstrating good performance.

Efficacy and outcomes of rescue screws in unstable pelvic ring injuries - A retrospective matched cohort study.

The emergency treatment of unstable pelvic ring injuries is still a challenge and requires surgical and anesthesiological resuscitation. Emergency fixation of the unstable pelvic ring with percutaneous sacroiliac (SI) screws, also known as "Rescue Screws", is an established treatment method. The aim of our study was to compare the outcome and complication rates of "Rescue Screws" with elective SI-screw fixations. A 1:1 ratio nearest-neighbor matched, retrospective cohort study of trauma patients with acute pelvic ring injuries at a level one trauma center was performed. Patients ≥ 15 years, treated with SI-screw fixation were included. pathologic fractures, missing consent and navigated procedures. The primary outcome parameters was defined as SI-screw revision operations. Patients were stratified according to treatment strategy (RS: Rescue Screws; EL: elective SI-screws). From 392 patients identified between 11/2014 and 08/2021, 186 met the inclusion criteria with 41 in the RS Group and 145 in the EL group. After matching, 41 patients were included in each group with similar baseline characteristics except persistent hemodynamic shock (RS: n = 22 (53.37%) vs. EL: n = 1 (4.3%), p < 0.001). Surgical characteristics were comparable in terms of instrumentation levels and insertion-sites. No significant differences were observed in the outcome parameters (revisions, reoperations, implant-associated complications, LOS and mortality) between both groups. Treatment of unstable pelvic ring fractures with Rescue Screws appears as a feasible treatment option for emergency stabilization. Rescue Screws are not associated with elevated revision rates and increased complications rates. This minimally invasive technique enables safe emergency stabilization of the posterior pelvic ring. Prospective or randomized clinical trials are required to directly compare Rescue Screws with other competing emergency stabilization techniques.

Monitoring process stability in robotic wire-laser directed energy deposition based on multi-modal deep learning

Robotized wire-laser directed energy deposition (DED) is a highly anticipated technology with excellent material utilization and deposition efficiency for fabricating complex-structure metal parts. Nevertheless, the immaturity of the monitoring and control techniques for the deposition process stability are the main challenges in achieving automatic and repeatable manufacturing of metal parts. This study proposes a novel approach to monitor the process stability, i.e., the intersection point between the laser beam and the wire to the top layer distance (IPTD), in robotic wire-laser DED based on a designed multi-modal IPTD estimation model and coaxial visual sensing. The novelty is that directly extracting deposition height features from coaxial molten pool images is attempted based on deep learning. In particular, the designed multi-modal IPTD estimation model, consisting of a convolutional neural network (CNN) part and a fully connected network, combines the features of molten pool images and process parameters to estimate the IPTD state. Six model architectures and three image pixel sizes are used in the IPTD classification tasks to determine the CNN part architecture and the input image pixel size of the multi-modal deep learning model based on classification results. The regression performances of established single-modal and multi-modal IPTD estimation models are studied and discussed. Compared to other model architectures, the ResNet-18 model possesses the highest convergence rate during training and the best classification accuracy of 0.9975 on the testing dataset with the image pixel size of 180 × 105. The fitting accuracy and generalization performance of the multi-modal IPTD estimation model are marked superior to the single-modal IPTD estimation model. Validation experiments reveal the effectiveness of the proposed monitoring approach of process stability. This study will lay a solid foundation for the future control of process stability in robotic wire-laser DED.

A Predictive Model Using Long Short-Time Memory (LSTM) Technique for Power System Voltage Stability

The stability of the operation of the power system is essential to ensure a continuous supply of electricity to meet the load of the system. In the operational process, voltage stability (VS) should be recognized and predicted as a basic requirement. In electrical systems, deep learning and machine learning algorithms have found widespread applications. These algorithms can learn from previous data to detect and predict future scenarios of potential instability. This study introduces long short-term memory (LSTM) technology to predict the stability of the nominal voltage of the power system. Based on the results, the recommended LSTM technology achieved the highest accuracy target of 99.5%. In addition, the LSTM model outperforms other machine learning (ML) and deep learning techniques, i.e., support vector machines (SVMs), Naive Bayes (NB), and convolutional neural networks (CNNs), when comparing the accuracy of the VS forecast. The results show that the LSTM method is useful to predict the voltage of an electrical system. The IEEE 33-bus system indicates that the recommended approach can rapidly and precisely verify the system stability category. Furthermore, the proposed method outperforms conventional assessment methods that rely on shallow learning.

Improved Control Technique for Enhancing Power System Stability in Out-of-Step Conditions

From time to time, a series of unpredictable and conflicting contingencies can lead to angular instability of the power system and even blackouts if not adequately handled by an out-of-step (OOS) protection system. The key contribution of this research work, to the theory of out-of-step protection, is the identification and isolation after a given disruption of many unstable swings. This paper presents a proposed method to avoid false operation for distance function by out-of-step blocking to improve the system stability by using optimally placed PMUs for the fast detection of system analogue quantities. The studies were performed on a modified Eskom transmission network in the Western Cape with 765 kV and 400 kV voltage levels. The aim is to investigate the IEC 61850-90-5 standard for predictive dynamic stability maintaining systems using PMUs for out-of-step conditions of synchronous generators. The power system modelling and simulation are performed in the RSCAD-FX for the proposed multi-area power system network. An experimental lab-scale implementation is built to test the proposed out-of-step algorithm in a real-time digital simulator. Software-based PMU is incorporated to test and validate the IEC 61850-90-5 standard sampled values. Simulation and experimental results are presented.

Output feedback control of stochastic nonlinear systems with external disturbances and inverse dynamics

SummaryThis work presents an approach to control a type of stochastic cascade nonlinear systems, which involve external disturbances and nonlinear terms. The external disturbances under the consideration are not measurable and regarded as extended states. The proposed method addresses the problem of unmeasured states and external disturbances by introducing an extended state observer (ESO). Based on the above work, a new stochastic nonlinear system including ESO is established. To ensure the stability and boundedness of the system, an adaptive output feedback controller is designed by using stochastic integrated input‐to‐state stability and backstepping design technique. This controller guarantees that all the states remain almost surely bounded and globally asymptotically stable in probability. Simulation experiments are conducted to validate the effectiveness of the proposed control scheme.

Combined Approaches for the Remediation of Cadmium- and Arsenic-Contaminated Soil: Phytoremediation and Stabilization Strategies

The prolonged duration of phytoremediation poses a risk of heavy metal dispersal to the surrounding environment. This study investigated a combined remediation approach for cadmium (Cd)- and arsenic (As)-contaminated soil by integrating phytoremediation with stabilization techniques. Bidens pilosa was utilized as the phytoremediator, and steel slag, pyrolusite, and FeSO4 were employed as stabilizing agents in the pot experiments. Key metrics such as soil moisture content, root length, plant height, and heavy metal concentrations in Bidens pilosa were measured to evaluate the remediation efficacy. Additionally, the bioavailability, leaching toxicity, and chemical forms of Cd and As, along with other soil properties, were analyzed. The results indicated that the optimal restoration effect was achieved by combining steel slag, pyrolusite, and FeSO4 with stabilizers in a ratio of 2:1:10. Additionally, the optimal dosage of these materials was found to be 9% by weight. Mechanistic studies, including heavy metal speciation analysis, X-ray photoelectron spectroscopy (XPS), and microbial community diversity analysis, revealed that the stabilization effects were primarily due to the interactions of anionic and cationic ions, chelation by organic acids secreted by plant roots, and enhanced microbial activity. A cost–benefit analysis demonstrated the technical, economic, and commercial viability of the combined remediation approach.

Unconditional MBP preservation and energy stability of the stabilized exponential time differencing schemes for the vector-valued Allen–Cahn equations

The vector-valued Allen–Cahn equations have been extensively applied to simulate the multiphase flow models. In this paper, we consider the maximum bound principle (MBP) and corresponding numerical schemes for the vector-valued Allen–Cahn equations. We firstly formulate the stabilized equations via utilizing the linear stabilization technique, and then focus on the bounding constant of the nonlinear function based on the fact that the extremes of a constrained problem will occur in the bounded and convex domain. Later the first- and second-order stabilized exponential time differencing schemes are adopted for temporal integration, which are linear and unconditionally preserve the discrete MBP in the time discrete sense. Moreover, the proposed schemes can be proven to dissipate the original energy instead of the modified energy. Their convergence analysis is also presented. Various numerical examples in two and three dimensions are performed to verify these theoretical results and demonstrate the efficiency of the proposed schemes.

Peat Stabilization by Using Ordinary Portland Cement (OPC) Mixed with Rice Husk Ash (RHA)

Peat generally consists of high organic and water contentthatcauses the strength of peat soil to be very weak to bear any load. The strength of the soil can be increased by using binders like cement in peat soil stabilizationtechniques, but excessive cement use can pollute the ecosystem. This study aimed to determine the ideal proportion of rice husk ash (RHA) to be utilized in place of cement. A test of the basic characteristics of peat soil is carried out in order to identify the nature of peat soil. The strength of treated and untreated peat soil was determined through an unconfined compression test (UCS). By replacement at 15%, the result shows the replacement of 15% RHA in Ordinary Portland Cement (OPC) demonstrates the maximum strength with the value of 531 kN/m² and 580 kN/m² for 7 and 28 curing days respectively. The microstructure image shows the difference in total porosity between the untreated and treated samples through the Scanning Electron Microscopy (SEM) test. A chemical test via Energy Dispersive X-ray (EDX) shows that the strength of samples improveswhen the amount of carbon reduces and calcium content increases. The findings illustrate that the utilization of discarded agricultural waste can be used as an additive in reducing the consumption of cement to increase the strength of peat based on soil stabilization techniques.