Wall Deformation Research Articles

Characterization of deep-sea sponge ground (Asconema setubalense) using structure from motion methodology.

The hexactinellid sponge Asconema setubalenseKent, 1870 is a deep-sea species characterized by its expansive cup-shaped morphology, which contributes significantly to the three-dimensional complexity of the marine ecosystems. This sponge forms grounds that offer protection to pelagic organisms and juvenile stages. Despite its ecological relevance, there is a lack of information on the ecology, behavior and population structure of this species. The research aimed to conduct a multitemporal analysis of this sponge in the Aviles Canyon System over a ten-year period, focusing on spatial distribution and abundance. Changes in fishing pressure were estimated using the presence of fishing gears as a proxy. Additionally, the study sought to provide a detailed morphometric description through 3D photogrammetric reconstructions based on the latest data. The multi-temporal analysis revealed a subtle increase in sponge density, particularly at depths ranging from 320 to 390 m, exhibiting an irregular spatial distribution in 2022, with maximal values of 0.08 individuals/m2. Despite a small decrease on the loss of fishing gears in the overlapping area between samplings in 2012 and 2022, there was not a clear indication of a decline in fishing pressure over the years. Notably, more sightings of fishing gears were found in transect IC222TV_16 (0.07 gears/m2) than in IC222_TV02 (0.04 gears/m2) in 2022, suggesting potential spatial preferences for fishing activities. Visual analysis of temporal populations revealed an increase of 7% in specimen perturbations over ten years, with the population in IC222_TV16 being healthier (9% of the individuals presenting severe deformations) than in IC222_TV02 (40%). High-density fishing gear locations coincided with areas inhabited by sponges displaying the highest perturbation levels in both transects. Morphometric analysis using data from 2022 indicated a prevalence of individuals with heights concentrated between 0.18 and 0.38 m, osculum and flounce diameters reaching 0.4 and 0.56 m and osculum and flounce surfaces of 0.02–0.04 and 0.06–0.19 m2 respectively. Over 80% of measured specimens exhibited a high degree of asymmetry. Strong correlations were observed between heights and osculum and flounce surfaces, but external factors may be included for explaining wall deformities. These findings contribute valuable insights into the characterization of A. setubalense, serving as a foundation for future research in the area. Moreover, this work highlights the promising potential of photogrammetry as an efficient tool for monitoring of vulnerable marine ecosystems (VME) and marine protected areas.

Prevalence and incidence of chest wall deformities in children below 18 years old: The first systematic review and meta-analysis

Prevalence and incidence of chest wall deformities in children below 18 years old: The first systematic review and meta-analysis

Evaluating the web as a source of information for patients with chest wall deformities: insights into engagement and disparities.

Recent data highlight the internet's pivotal role as the primary information source for patients. In this study, we emulate a patient's/caregiver's quest for online information concerning chest deformities and assess the quality of available information. We conducted an internet search using combination of the terms "pectus excavatum," "pectus excavatum surgery," "funnel chest," "pectus excavatum repair" and identified the first 100 relevant websites from the three most popular search engines: Google, Yahoo, and Bing. These websites were evaluated using the modified Ensuring Quality Information for Patients (EQIP) instrument. Of the 300 websites generated, 140 (46.7%) were included in our evaluation after elimination of duplicates, non-English websites, and those targeting medical professionals. The EQIP scores in the final sample ranged from 8 to 32/36, with a median score of 22. Most of the evaluated websites (32.8%) originated from hospitals, yet none met all 36 EQIP criteria. None of the evaluated websites pertaining to pectus excavatum achieved a flawless "content quality" score. The diverse array of websites potentially complicates patients' efforts to navigate toward high-quality resources. Barriers in accessing high-quality online patient information may contribute to disparities in referral, patient engagement, treatment satisfaction, and overall quality of life. IV.

Effect of stiffness of building adjacent to excavation on deformation of the excavation wall

Effect of stiffness of building adjacent to excavation on deformation of the excavation wall

Can a Breast Augmentation Procedure Improve the Appearance of Pectus Excavatum Deformity in Female Patients? A Prospective Study.

This study evaluates a specific breast augmentation (BA) technique in patients with pectus excavatum(PE) and its results in improving this deformity, augmenting the breasts, and correcting the concurrent breast asymmetry. Twenty-eight patients with PE were treated from 2017 to 2021. All patients who visited our private practice were aiming to augment their breasts, correct their breast asymmetry, and improve their PE. The mean age of the patients was 25 years. In most cases, the submuscular dual-plane technique was chosen. Patients' quality of life regarding their chest wall deformity was assessed using the Single Step Questionnaire (SSQ). Subjects' quality of life regarding general self-esteem, psychosocial well-being, and physical function were assessed at initial screening and 24-month follow-up using the BREAST-Q V2 questionnaire. Also, patients filled out a pain-evaluating questionnaire concerning the first 5 postoperative days to determine the recovery of this specific technique. No complications were observed. The SSQ revealed high satisfaction (mean score=73) and significant (P = 0.001) improvement following the operation. The improvements regarding psychosocial well-being, sexual well-being, and satisfaction with the BREAST-Q were also equally high (P = 0.001). The pain was minimal during the first five postoperative days. This is the first prospective study that evaluates the quality of life using both the SSQ, the validated BREAST-Q, and the pain score when performing BA in patients with PE and breast asymmetry using breast silicone implants. BA is a procedure that can give excellent results both regarding chest wall deformity and BA in PE patients.

The 3D response of a large-scale masonry arch bridge – Part II: Performance at failure

Masonry arch bridges continue to form a pivotal part of the transport networks of the UK and many other countries worldwide. However, their three-dimensional response (3D) under loading has to date been relatively little investigated. Here, details of a large-scale masonry arch bridge load tested to failure under laboratory conditions are presented. The bridge consisted of a brickwork arch barrel, abutments, spandrel walls, and compacted limestone as backfill material. Patch loading was applied to the surface of the backfill at the quarter and three-quarter span points to assess the failure mechanism, load-carrying capacity, and residual strength of the bridge. A range of sensors were employed to capture the 3D bridge response and ground-penetrating radar surveys were performed on both the virgin and load-tested bridge to compare its internal structure. The observed evolution of cracks and post-test deformed geometry demonstrated the presence of both a localised 3D mode of response in the arch barrel in the vicinity of the applied load and a global four-hinge mechanism. Failure-level load tests carried out first at the quarter span and then at the three-quarter span points showed that the load-carrying capacity of the bridge had reduced by only 10 % in the second test, though the stiffness of the bridge had decreased by around 35 %. During the failure-level load tests, significant in-plane and out-of-plane deformations of the spandrel walls were also observed, adding to the much smaller residual deformations recorded in low- and mid-level load tests.

An analytical formula evolved from thermal-structural coupling model for life prediction and structural design of reusable thrust chambers

The thermal-structural analytic model is essential for the life prediction of reusable rocket thrust chambers. The common numerical model based on the finite element method is computationally intensive. In order to simplify the life prediction method and improve the calculation efficiency, a thermal-structural analytical formula is proposed. The one-dimensional analytical heat transfer algorithm for accurately calculating the temperature of the thrust chamber is established, and Porowski’s beam model for calculating the structural deformation is adopted. Finally, the analytic formula for life prediction is directly established by reasonable simplification. This is an algebraic solution describing the relationship between life and the cooling channel parameters, and the computational efficiency is improved by about 12,000 times. The calculated temperature and deformation of the inner wall are verified by the finite element method with an error of less than 10 %, indicating the proposed analytical formula is accurate. Further, the analytical formula is applied to design the cooling channel parameters according to the given target life. The structural design method is validated by numerical simulation and experimental data. The analytical formula and the structural design method provide new ideas for the analysis and design of reusable rocket engines, which have broad application prospects.

Pectus carinatum, small pneumothorax, and Brugada patterns: First description and pathophysiological analysis

Pectus carinatum is a chest wall deformity where the breastbone and ribs protrude outward, sometimes referred to as “pigeon chest” due to the bird-like appearance of the chest. This condition occurs in approximately 1 in 1000 children, more commonly affecting boys than girls. Pectus carinatum tends to worsen as a child grows, especially during puberty, with about 15% of the children experiencing associated conditions like scoliosis. We present a case report of a young patient with pectus carinatum who experienced a small right apex pneumothorax and exhibited Brugada patterns on electrocardiogram tracing. This is the first clinical case reporting Brugada pattern presentation in both a patient with pectus carinatum and a small pneumothorax. We have conducted a clinical anatomical and electrocardiographic analysis to explore a physiopathological explanation for these findings, considering that our patient has no history or clinical signs of Brugada Syndrome. To further elucidate the clinical, anatomical, and electrocardiographic findings observed in our patient, detailed analyses were conducted. These investigations focused on how the pectus carinatum may influence electrocardiographic patterns through structural alterations of the thoracic wall, potentially modifying the transmural electrical field across the myocardium. This analysis aimed to explore a physiopathological explanation for the Brugada patterns observed, considering our patient’s unique thoracic anatomy and the absence of clinical Brugada Syndrome. We conclude that: 1. Pectus carinatum may create a window that facilitates the less resistive measurement of cardiac action potentials; 2. Small pneumothoraces can induce modifications in the cardiac electrical signal detected by surface electrodes, and pectus carinatum could unmask these modifications; and 3. Surface electrodes may measure subepicardial potentials that include and are modified by adjacent pericardial tissues, potentially resulting in alterations in transmural potential differences, thus producing fictitious Brugada patterns. Similarly, there is a possibility that the right ventricular outflow tract may be included within the subendocardial potentials.

Performances of a large-scale deep excavation with multi-support types and zoned excavation technique in Shanghai soft soil

This paper presents a comprehensive field investigation on a large-scale deep basement excavation in Shanghai soft soil propped by a multi-support system. Because of its large size, irregular shape, and different excavation depths, the excavation site was divided into Zone A and Zone B to optimize the construction process and improve the construction efficiency. The excavation was constructed using the “bottom-up” method following the principles of stratification and zone excavation. A notable innovation in this project is the implementation of three different support subsystems as a multi-support system to accommodate different deformation requirements in different areas. The excavation was densely instrumented to monitor the behaviors of retaining walls, columns, axial forces of struts, and surrounding ground throughout the whole construction process. The wall deformation and ground surface settlement of the three support subsystems are comprehensively compared to investigate the performances of the three support subsystems. The comparison of the corner-effect envelope summarized from nine reported cases indicates that the multi-support system can effectively alleviate the spatial corner effects of the excavation. The zoned construction technique in conjunction with the multi-support system presented in this case study provides an efficient and economic approach for large-scale deep excavation in soft soils.

CURRENT APPROACHES TO MANAGING MICROTIA

Microtia, a developmental anomaly of the external ear resulting in a deformed auricle, affects 1 to 5 individuals per 10,000. Literature suggests a male predominance, with nearly 2.5 times more male patients affected than females. Additionally, there is a notable right-sided predilection, leading to pronounced asymmetry, observed in approximately 83% of cases. Surgical reconstruction is the primary treatment for microtia, albeit a technically demanding procedure with challenges in achieving optimal aesthetic outcomes. Reconstruction typically involves autologous costal cartilage, known for its effectiveness but requiring advanced surgical skills. Complications, including pneumothorax, postoperative pain, chest wall deformity, and pathological scarring, are common with this approach. In recent years, surgeons have increasingly adopted modern techniques utilizing porous high-density polyethylene implants for reconstruction. This approach is gaining popularity due to the challenges associated with achieving satisfactory cosmetic results using autologous costal cartilage reconstruction. Based on the bibliosemantic and analytical methods employed to analyze the literature, we posit that this topic necessitates further investigation and a multidisciplinary approach. The involvement of otolaryngologists and maxillofacial surgeons is imperative for the comprehensive treatment of this pathology.

Experimental study on the load bearing behavior of shored mechanically stabilized earth wall

Shored mechanically stabilized earth (SMSE) walls have been increasingly applied in the projects of widening existing roads or new construction of roads on slopes because of their good carbon emission reduction and mechanical performance. In this paper, a scaled-down model test of SMSE wall with shoring wall batter of 1H:2V was conducted to study the load-bearing behavior of SMSE wall under this terrain condition, and the results including wall deformations, earth pressures, reinforcement strains, and potential failure surface were analyzed. The results show that although the backfill near the shoring wall was not directly compressed by the load, it still slipped along the backfill-shoring wall interface. The loading created a tensile pressure zone in the upper part of the backfill-shoring wall interface, which may lead to tensile cracking. The uppermost layer of geogrid was more prone to sliding, while the tensile deformation was smaller, and its strain value was overall smaller than the strain value of the geogrid below it. As the load increases, the potential failure surface changed from a Rankine failure surface to a bilinear potential failure surface. The potential failure surface did not pass through the heel of the SMSE wall under large loads.

Development of multi-sensors fusion monitoring system for shaft wall deformation

Ensuring shaft safety is crucial for underground coal mining. The prevailing method for monitoring shaft deformation involves manual measurements conducted regularly, necessitating numerous surveyors to descend into the shaft. This approach is laborious and time-consuming, and its reliance on human intervention significantly affects accuracy. An emerging alternative employs an enhanced laser slam scanner comprising laser ranging and inertial navigation angle measurement modules. The accuracy of the inertial navigation angle often requires refinement through laser point cloud registration to mitigate errors. However, existing research has not explored the utilization of a single inertial navigation sensor within a shaft, which potentially influences measurement outcomes. To investigate the impact of inertial navigation angle measurement errors from lidar scanners on shaft interior measurements and propose corresponding error reduction methods, this study developed a multisensor fusion system for monitoring shaft wall deformations. Three experiments were conducted to assess the accuracy of this monitoring system: a laboratory experiment, a simulated experiment, and a real shaft experiment. The results demonstrated that the maximum mean absolute errors (MAEs) in the laboratory and simulated shaft experiments were 0.06 cm and 0.30 cm, respectively, validating the reliability of the point cloud processing algorithm. In the real shaft experiment, the maximum MAE was 0.48 cm, confirming the measurement accuracy of the monitoring system. Compared to manual measurements, the system reduced the measurement time by 48% and streamlined the process from 12 to 3 steps. These findings highlight the monitoring system’s centimeter-level accuracy, efficiency in reducing measurement time, simplification of the measurement process, and elimination of the need for human entry into the shaft.

How borehole wall elasticity affects wellbore storage capacity in periodic hydraulic tests

Characterizing fluid transport and pore pressure diffusion is key for monitoring and understanding many natural (e.g., seismically active zones and volcanic systems) and engineered environments (e.g., enhanced geothermal reservoirs and CO2 underground storage). Borehole hydraulic testing allows for inferring relevant properties of the probed subsurface volume, such as, for example, its transmissivity and diffusivity, assessing the governing flow regime as well as detecting the presence of hydraulic boundaries. Periodic hydraulic tests (PHT) achieve these objectives using an oscillatory fluid injection procedure while measuring the fluid pressure response in monitoring boreholes. The relevant information on the pressure diffusion process occurring in a probed formation is retrieved from the phase shifts and amplitude ratios between the flow rate and the interval pressure. In general, the interpretation of PHT data relies on the assumption that the pressure diffusion process is largely unaffected by the deformation of the probed rock volume. To assess this assumption, we present a conceptual PHT model based on the theory of poroelasticity to investigate the role played by hydromechanical coupling (HMC) effects during PHT and to assess whether and to what extent additional mechanical information can be extracted from these tests. These effects include the influence of the borehole wall deformation on the wellbore storage coefficient Sw, which quantifies the difference between the injected flow rates and those actually entering the porous formation. We show that, in homogeneous formations, the commonly taken approach based on the uncoupled diffusion solution for radial flow reproduces the results of our HMC model. However, neglecting the deformation effect of the borehole wall on the storage capacity of the system during injection can lead to underestimations of both transmissivity and diffusivity, particularly at shorter oscillation periods. We present analytical expressions for the borehole wall deformation contribution to Sw, which depends on the shear modulus and does not change with the oscillatory period. We show that it is possible to obtain the effective Sw along with the transmissivity and diffusivity using observations at various oscillatory periods. In the presence of hydraulic boundaries, such as no-flow or constant-pressure boundaries, at a given distance from the injection borehole, Sw becomes period-dependent, introducing apparent variations in the inferred shear modulus of the formation if the associated HMC effects are not accounted for. Our results thus highlight the importance of accounting for HMC effects in PHT data interpretation, not only to reliably and accurately characterize and monitor hydraulic properties but also to fully exploit the potential of PHT to provide additional information on the mechanical behavior of the probed rock volume.

Tapping into fungal potential: Biodegradation of plastic and rubber by potent Fungi

Plastic polymers are present in most aspects of routine daily life. Their increasing leakage into the environment poses a threat to environmental, animal, and human health. These polymers are often resistant to microbial degradation and are predicted to remain in the environment for tens to hundreds of years. Fungi have been shown to degrade complex polymers and are considered good candidates for bioremediation (biological pollutant reduction) of plastics. Therefore, we screened 18 selected fungal strains for their ability to degrade polyurethane (PU), polyethylene (PE), and tire rubber. As a proxy for plastic polymer mineralization, we quantified O2 consumption and CO2 production in an enclosed biodegradation system providing plastic as the sole carbon source. In contrast to most studies we demonstrated that the tested fungi attach to, and colonize the different plastic polymers without any pretreatment of the plastics and in the absence of sugars, which were suggested essential for priming the degradation process. Functional polymer groups identified by Fourier-transform infrared spectroscopy (FTIR), and changes in fungal morphology as seen in light and scanning electron microscopy (SEM) were used as indicators of fungal adaptation to growth on PU as a substrate. Thereby, SEM analysis revealed new morphological structures and deformation of the cell wall of several fungal strains when colonizing PU and utilizing this plastic polymer for cell growth. Strains of Fusarium, Penicillium, Botryotinia cinerea EN41, and Trichoderma demonstrated a high potential to degrade PU, rubber, and PE. Growing on PU, over 90 % of the O2 was consumed in <14 days with 300–500 ppm of CO2 generated in parallel. Our study highlights a high bioremediation potential of some fungal strains to efficiently degrade plastic polymers, largely dependent on plastic type.

Self-organising maps in the analysis of strains of human abdominal wall to identify areas of similar mechanical behaviour

The study refers to the application of a type of artificial neural network called the Self-Organising Map (SOM) for the identification of areas of the human abdominal wall that behave in a similar mechanical way. The research is based on data acquired during in vivo tests using the digital image correlation technique (DIC). The mechanical behaviour of the human abdominal wall is analysed during changing intra-abdominal pressure. SOM allow to study simultaneously three variables in four time/load steps. The variables refer to the principal strains and their directions. SOM classifies all the abdominal surface data points into clusters that behave similarly in accordance with the 12 variables. The analysis of the clusters provides a better insight into abdominal wall deformation and its evolution under pressure than when observing a single mechanical variable. The presented results may provide a better understanding of the mechanics of the living human abdominal wall. It might be particularly useful when selecting proper implants as well as for the design of surgical meshes for the treatment of abdominal hernias, which would be mechanically compatible with identified regions of the human anterior abdominal wall, and possibly open the way for patient-specific solutions.

Mixed convection in a variable size cavity: Effect of flexible wall characteristics

Boosting the mixed convection in vented cavities using a moving wall results in a disturbed strong circulation. This study investigates the mitigation of the disturbed circulation to promote the transfer of heat by providing additional size to the circulation. The use of deformable walls with different thicknesses, lengths and modulus of elasticity is suggested for this problem. The top wall of the cavity is adiabatic and moves in the positive direction, and four speeds were studied; 0.5, 1, 2 and 4 times the fluid velocity at the inlet vent. The ratio of the natural to forced convection is controlled by ranging Richardson number by 0.01 ≤ Ri ≤ 100. Three aspect ratios are studied; AR = 0.5 (horizontal cavity), 1 and 2 (tall cavity). The problem is treated numerically using the finite element method. Results indicate that the fluid flow inside the vented square cavity changes from major single vortices into multi vortices at high (Ri = 100). Results affirm that a flexible wall yields a higher Nusselt number than the rigid wall, it's about 12 %, and 20 % for Ri = 0.01 and 10, respectively. A thicker flexible wall augments the Nusselt number for Ri ≤ 10. For specified conditions, the Nusselt number of the horizontal cavity is 17.7 % greater than the tall cavity. The lid speed of uLid = 4 uin exhibits a competent role in raising the Nusselt number for low Richardson number.

Effects of oil heat treatment on poplar wood properties: A pilot scale study

Pilot-scale oil heat treatment was conducted to enhance the quality of poplar wood obtained from a fast-growing plantation. Three target temperatures, namely 180, 190, and 200 ˚C, were chosen for the oil heat treatment process. Clear, small specimens were cut from the lumber, following the prescribed standards for assessing wood quality. Light microscopy revealed the ruptures and deformation of the wood cell wall as the treatment temperature increased. The volumetric swelling of the treated specimen decreased proportionally with the increase in treatment temperature. The impact of oil heat treatment on the mechanical properties of wood varied depending on the specific type of mechanical strength and processing temperature. The modulus of rupture, toughness, and hardness of the treated specimens drastically decreased at 200°C. However, the specimens treated at 200°C exhibited much lower mass loss during the fungal decay test. The results of the analytical test showed an increase in the crystalline cellulose content and thermal stability of the treated wood, due to the thermal degradation of hemicelluloses and amorphous regions of cellulose. Overall, it is concluded that oil heat treatment of poplar wood in the optimal temperature is an efficient approach to upgrade its quality with minimal reduction in mechanical strength.

Characteristics of Deformation and Stability of Ultra-Deep Pit in Plateau Alluvial–Lacustrine Gravel Strata

Deformation of ultra-deep pit walls and surrounding geotechnical bodies due to engineering disturbances typically shows intricate spatiotemporal patterns. In this study, deformations at critical steps of the construction process were first numerically simulated by Midas GTS NX, and this was followed by lab-scale geophysical model tests of the entire process of the pit construction. Data on deformation obtained from numerical simulations and lab-scale geophysical model tests were compared with those obtained from a dynamic monitoring scheme in the field to analyze the characteristics of the deformation and evolution of the pit wall. This was used to derive a generally applicable theoretical expression to predict variations in the horizontal displacements.

MODELING OF AORTIC DEFORMATION IN ANEURYSM AND WALL DISSECTION

The deformations of aortic walls in case of aortic aneurysm (dilation) and aortic wall dissection are studied. Numerical calculations of the load on the aortic walls at aneurysm and aortic wall dissection are carried out. It is shown that rupture of the inner layer of the vessel leads to an increase in the stress on the outer wall of the vessel. Increasing the thickness and length of the rupture increases the stresses on the outer wall of the vessel. The presence of an aneurysm of the vessel increases the stresses compared to a vessel without an aneurysm. Splitting of the inner wall of the vessel leads to an increase in the stresses on the wall - stresses decrease with increasing rupture width for a straight vessel and increase for a vessel with an aneurysm.

Cavern spacing of CAES cavern group in hard rock based on plastic zone and deformation analysis

Existing research on layout parameters of compressed air energy storage (CAES) cavern groups in hard rock has indicated that the key influential factors for group stability include buried depth, diameter, and cavern spacing. Among these, in contrasting to other factors, the research on cavern spacing is limited. This paper focuses on the issue of safe spacing and proposes a numerical method to determine it. By establishing a series of finite element models, the stress state of surrounding rock, changes in shape, equivalent plastic strain of plastic zone, and cavern wall deformation under different spacing have been studied. When a group of air storage caverns in rows is subjected to high internal pressure, for a small spacing, the plastic zone of the surrounding rock between two caverns is connected. Here, the size of the plastic zone, equivalent plastic strain value, and deformation of the cavern wall are relatively large, making the surrounding rock highly susceptible to damage. As the spacing increases, the horizontal width of the plastic zone, the maximum equivalent plastic strain value, the displacement changes of the cavern wall remain stable. This spacing is virtually the same as that when the plastic zone of the surrounding rock is no longer connected and can be selected as a safe spacing. This study explores the design of cavern safe spacing of underground CAES cavern groups and discusses several influencing factors, which can provide references for follow-up energy storage engineering and research.