Section Of Wall Research Articles

Development and Evolution of Icy Layer Outcrops on Mars' North Polar Ice Cap: Observations of Vertical and Lateral Variability

AbstractMars' north polar ice cap features troughs that cut into the ice, exposing subsurface layers of different brightness and topographic expression. Specifically, these layers represent two different stratum types: lower albedo (higher dust content) marker beds, which protrude out of the wall topographically, and higher albedo (i.e., icier) interbeds, which are recessed compared to the marker beds. Here, we investigate the role of local‐scale processes by performing a detailed geomorphic characterization of variability in these strata across two sites, using a novel approach to calculating true layer protrusion which utilizes data from high‐resolution Digital Terrain Models. We measure protrusions of the order of meters but find lateral variations within a single trough exposure, suggesting a role for local‐scale processes in the evolution of the layers. We find that the topographic relief of protruding marker beds decreases as a function of decreasing trough slope and brightness (a proxy for dust cover/content). We also observe the presence of an insulative allochthonous dust veneer present on discrete sections of the trough wall, which we suspect plays an important role in modulating ice loss from the trough walls. A companion paper (Bramson et al., 2025, https://doi.org/10.1029/2024JE008360) models the contribution of insolation‐induced sublimation to present a new framework, and potential timescales for the development of the marker bed protrusion observed here.

Evaluation of plasterboard partition wall sections in terms of requirements for noise control

Evaluation of plasterboard partition wall sections in terms of requirements for noise control

Методологические основы адаптации параметров буровзрывных работ к изменяющимся горно-геологическим условиям при разработке сложноструктурных месторождений

The article addresses the issues of improving the design and implementation of process blasts of complex-structured rock masses in open-pit mining of solid minerals. The stages of adaptation are presented for the drilling and blasting technology in the new mining conditions in open pits of the Ural region, Siberia, Karelia and Kazakhstan. Systematization of the main factors that define the conditions for changing the drilling and blasting parameters is shown based on the data on in-situ physical and mechanical characteristics of rocks. The article shows transient processes in the classified form, which are used as the basis for the development of fundamental methodological principles for adapting the equipment and technology of drilling and blasting operations to the variable conditions of mining complex-structural deposits of solid minerals. A methodological approach is based on the established specific experimental data: the heterogeneity of the rock mass in terms of fracturing according to the roller-bit drilling data; the relationship between the detonation rate of emulsion explosives and the density and diameter of the explosive charge in its different ranges, the influence of the degree of attenuation of seismic blasting oscillations on the rate of displacement of the protected sections of the open pit walls at different directions of the explosive charge priming.

DIFFERENTIAL MUELLER-MATRIX MAPPING OF THE POLYCRYSTALLINE COMPONENT OF BIOLOGICAL TISSUES OF HUMAN ORGANS

The article presents the materials of diagnostic application of the method of differential Mueller-matrix mapping of optically anisotropic architectonics of the layers of soft matter of the female reproductive sphere – histological sections of uterine biopsy. The efficiency and accuracy of differential diagnostics of benign and precancerous conditions of endometrial tissue are considered using statistical analysis of algorithmically reproduced maps of average values of linear and circular birefringence and dichroism parameters of optically anisotropic architectonics of representative samples of native histological sections of the uterine wall. The values of the balanced accuracy of differential diagnostics are presented by using the technique of statistical analysis of coordinate distributions of the mean values of the optical anisotropy parameters.

Simulations of divertor designs that spatially separate power and particle exhaust using mid-leg divertor particle pumping

Predictive design modeling of a Dissipation-Focused Divertor for future operation in DIII-D reveals that increasing the poloidal distance of the pump duct entrance from the target surface along the low-field side divertor baffle increases neutral compression and modifies the spatial distribution of power dissipation. With a divertor pump located mid-leg between the target and the X-point, SOLPS-ITER boundary plasma simulations without drifts predict the formation of a dense neutral cloud near the target with > 30x higher neutral compression in detachment, a more stable detachment front located further from the target, and ∼ 25 % lower outer midplane separatrix density required for detachment onset, compared to a pump located in the scrape-off layer at the target surface. Up to 19 MW of power flowing into the divertors is modeled using the following two numerical implementations for particle pumping: a specified fraction of particles incident on variable wall sections of the plasma grid is removed from the computational domain (so-called albedo pumping), and a pump duct is modeled which includes dynamics of kinetic neutrals in the duct. The simulations show that the detachment front is located between the divertor target and the X-point and is relatively stable near the pump entrance, without a strong dependence on gas puff rate or injected power. The mid-leg pump design spatially separates the two primary functions of a divertor (power handling and particle exhaust), with the majority of power dissipation occurring near the target plate and particle exhaust taking place further upstream. The benefit of enhanced dissipation using mid-leg pumping comes at the cost of a higher outer midplane separatrix density for a given amount of particle injection.

An Example of Using Low-Cost LiDAR Technology for 3D Modeling and Assessment of Degradation of Heritage Structures and Buildings.

This article examines the potential of low-cost LiDAR technology for 3D modeling and assessment of the degradation of historic buildings, using a section of the Koszalin city walls in Poland as a case study. Traditional terrestrial laser scanning (TLS) offers high accuracy but is expensive. The study assessed whether more accessible LiDAR options, such as those integrated with mobile devices such as the Apple iPad Pro, can serve as viable alternatives. This study was conducted in two phases-first assessing measurement accuracy and then assessing degradation detection-using tools such as the FreeScan Combo scanner and the Z+F 5016 IMAGER TLS. The results show that, while low-cost LiDAR is suitable for small-scale documentation, its accuracy decreases for larger, complex structures compared to TLS. Despite these limitations, this study suggests that low-cost LiDAR can reduce costs and improve access to heritage conservation, although further development of mobile applications is recommended.

Qualitative Analysis of the Heat Transfer in a Package of Square Steel Sections.

During the heat treatment of square or rectangular steel sections, a heated charge, arranged in regular packages, is placed inside a furnace. This type of charge forms a porous medium through which a complex heat flow occurs during heating. Several heat transfer mechanisms act simultaneously within this medium: conduction through the section walls, conduction and natural convection within the gas, thermal radiation between the section walls, and complex heat transfer (mainly contact conduction) at the joints between the adjacent sections. This article presents a qualitative analysis of heat transfer, aiming to determine the contribution of individual heat transfer mechanisms to the overall process. For this purpose, an analytical model of complex heat transfer within the package was employed, based on the thermo-electric analogy. The results from experimental studies were used to calculate the natural convection and heat transfer at the joints. It was assumed that the material of the sections was low-carbon steel, and the gas was air. Calculations were performed for the temperature range of 25 °C to 700 °C, considering three different geometrical configurations of the sections. It was shown that the effective thermal conductivity (ETC) of the package for the considered geometrical cases varies between 2.2 and 10.6 W/(m·K), which is an order of magnitude lower than the thermal conductivity of the individual sections. This parameter increased dynamically with the temperature. Moreover, the heat transfer intensity within the package of sections was nearly an order of magnitude lower than the heat conduction observed in a solid steel charge. Additionally, it was shown that the primary heat transfer mechanisms governing the heating process were thermal conduction (in the lower temperature range-up to approximately 350 °C) and thermal radiation (in the higher temperature range-above 350 °C). The gas convection inside the sections had a minimal impact on the heating process of the package. The primary parameters influencing the quality of the results were the joint resistance between the adjacent sections and the emissivity of the sections. The presented model can be used for the optimization of heat treatment processes for the considered charge.

Free convective flow of Ostwald-de Waele fluid in a Π-shaped cavity with heated strip and lateral wall cooling

This paper studies the free convection of Ostwald-de Waele fluid in a Π-shaped chamber with a Π-shaped heated strip at the lower mid-section. The upper wall and the remaining sections of the lower wall are thermally insulated, while the lateral walls are maintained at a low temperature. The primary objective is to identify the optimal power-law index (n) and the geometric configurations of the strip that yield enhanced heat transfer. Furthermore, the impact of Rayleigh number (Ra) on the thermal performance of the cavity in that optimum condition is to be investigated. The Galerkin finite element approach has been employed to resolve the governing equations and auxiliary conditions. Within the study, the power-law index of the Ostwald-de Waele fluid has been systematically varied (0.6 ≤ n ≤ 1.4). At the same time, the variations in the non-dimensional height (0.1 ≤ ζ ≤ 0.5) and width (0.1 ≤ ε ≤ 0.3) of the heated strip have been explored. The results show improved thermal performance with a growth in Rayleigh number, particularly when n < 1. The average Nussetl number for n = 0.6 at Ra = 106 is approximately 14 % higher than for n = 1.4. The findings further indicate an increment of 35 % in the heat transfer rate when the height of the strip decreases from 0.5 to 0.1. This investigation provides valuable insights into the natural convection phenomena of Ostwald-de Waele fluid in complex geometries, paving the way for advanced thermal management techniques in various engineering applications.

Giant uterine fibroid with phlegmona of the anterior abdominal wall

This report presents a rare case of giant uterine fibroids in a 52-year-old patient, which was complicated by phlegmon of the anterior abdominal wall. Physical examination revealed skin necrosis above the navel, measuring 12×10 cm, with purulent content. On palpation, a space-occupying formation reaching the xiphoid process was noted, indicating an abdominal distension. The patient underwent surgery as planned; a suppurated section of the anterior abdominal wall, extending to the aponeurosis, was placed on the operating table. An inferomedial laparotomy with excision of a necrotic, suppurating area of the anterior abdominal wall was performed. Furthermore, a mass in the abdominal cavity was removed using a blunt and sharp method, and extirpation of the uterus and appendages was conducted. Histological examination revealed a giant uterine leiomyoma with stromal hyalinosis and omentitis. The patient was discharged on postoperative day 10 in satisfactory condition. No complications were observed during the postoperative period. Advanced uterine fibroids are common, and ignoring the need to undergo regular medical examinations and insufficient medical examination coverage can lead to such complications, which can significantly affect the quality of life of patients.

Discovery and Reconstruction of the Remains of the Beacon-Equipped Hollow Enemy Towers along the Ming Great Wall

Hollow Enemy Towers, as iconic structures of the Ming Great Wall, are renowned for their roles in defense surveillance, weapon storage, and firearm operation. Recent studies have indicated that certain Hollow Enemy Towers along the Ji Town section of the Ming Great Wall also serve the function of Beacon Towers for beacon signaling. However, previous studies have not definitively determined if these towers were distinctively marked, nor have they provided a comprehensive account of their current distribution and original historical appearance. This paper initially examined the historical documentation of white lime markings employed on the outer walls of certain Hollow Enemy Towers, which served as Beacon Towers during the middle and late Ming periods. Utilizing multidisciplinary methodologies, this research identified remains of lime markings of the Beacon-Equipped Hollow Enemy Towers along the Ji Town section of the Ming Great Wall, illustrating their extensive distribution. We analyzed the material composition and construction techniques of the lime mortar. This analysis clarifies the scope of lime plastering on the exterior walls of these towers and offers a point of reference for restoring their original historical appearance. The results make a significant supplement to the types of signaling structures on the Great Wall, enriching existing understanding of the original appearance of the Great Wall’s historical landscape.

CONCEPTUAL ANALYSIS ON THE IMPACT OF ACOUSTIC LINERS IN FAN FLUTTER

Abstract This work investigates the impact of acoustically treated intakes on fan flutter. The propagation of the fan acoustic perturbations is studied using a simplified model, where the frequency of the waves in the intake is the natural frequency of the fan blade in the stationary frame of reference. The model consists of a constant cross-section annular duct, where the acoustic modes are computed for hard wall and lined wall regions, assuming a uniform axial flow. The interfaces between the lined and hard wall sections are solved by doing mode matching. The acoustic reflections in the zero-thickness intake are computed using the Wiener-Hopf technique following Rienstra's model. Analytical results show that the waves propagating from the fan are reflected and scattered radially at the interfaces between the hard wall and the liner. Furthermore, the liner damps and changes the phase velocity of acoustic modes. Due to the low frequency of the flutter waves, the radial scattering can activate different cut-off modes, which need to be retained in order to make accurate predictions. The likelihood of fan flutter is estimated using the phase of the reflected cut-on waves reaching the fan. This strategy is used to assess the impact of the acoustic liners on the stability of a realistic fan. It is concluded that the impact of the phasing and reflections induced by the acoustic liners is comparable to that of the intake and can alter the flutter characteristics of the fan significantly.

Optimal Design of Shear Wall Sections Considering Different Stress-Strain Relationships of Steel According to Eurocode 2

The present paper highlights the usefulness of bi-linear stress strain relationship of steel with inclined plastic branch with respect to horizontal plastic branch for slender rectangular shear wall design. The inclined branch refers to strain hardening of steel for which, stresses also increase with strain beyond the yield point. This significantly complicates the solution process for load-based design approach as adopted in flexure design. For design of sections subjected to axial forces with flexure, capacity-based approach of design is adopted instead of load-based design. Hence, the myth that the inclined plastic planch will lead to cumbersome and tedious calculations does not seems to hold good for capacity-based design approach which is adopted for design of columns and shear walls. In the present paper using different strength classes of concrete as permitted by the latest version of Eurocode2 (2023) and strength of steel, fyk= 500 MPa along with different ductility classes have been used for the development of P-M interaction charts for rectangular shear walls with uniformly distributed vertical reinforcements. An average of 12.26% and 3.42% increment in moment capacity values have been obtained in under reinforced and over reinforced failure conditions respectively between charts prepared by inclined and horizontal plastic branch.

Determination of Thermal Properties of Autoclaved Aerated Concrete Wall Sections Constructed with Distinct Mortars by the Experimental and Theoretical Data

This study investigated the thermal properties of autoclaved aerated concrete(AAC) wall sections constructed with distinct mortars. Within the scope of the study, four distinct wall sections of 25x25x5cm dimensions were created using AAC special adhesive mortar, cement mortar, lime mortar and cement-lime mortar. The thermal conductivity(λEXP) that was determined by the heat flow meter(HFM) method and bulk density(ρEXP) of each wall section was determined in the laboratory. Specific heat values(cEXP) of mortars and aerated concrete material were determined experimentally in the study. The thermal diffusivity value(αEXP), thermal effusivity value(eEXP) and volumetric heat capacity(VHCEXP) of each wall sample were calculated using the experimental data obtained in the laboratory. In addition, αTEO, eTEO and VHCTEO of each wall sample were calculated theoretically using the thermal conductivity, bulk density and specific heat value given in the literature and standards for the same wall sections. In the study, experimental data was compared to the theoretical data. As a result, the thermal properties of walls constructed with distinct mortars and thermal differences formed in the walls due to the effect of these mortars could be determined with experimental data. However, it was observed that theoretical data were insufficient to detect these thermal differences.

Performance analysis of the adaptive cycle engine with cooling air: From propulsion performance, thermodynamic efficiency, exergy and infrared characteristics

The adaptive cycle engine gains significant attention due to its variable thermodynamic cycles and multi-duct characteristics, which are utilized for thermal management to enhance engine performance. This paper explores the features of multi-duct technology in adaptive cycle engines and aims to improve engine flight performance. An analysis is conducted on the impact of duct air bleed on engine propulsion characteristics, thermodynamic cycle properties, and exhaust system infrared radiation characteristics. Initially, a component-level model of the adaptive cycle engine was established, considering CDFS duct, bypass duct, and third duct air cooling devices. This model uses the ducted cold air to cool the temperature of low-pressure turbine exit, center cone wall, and main nozzle expansion section wall. Subsequently, a method for analyzing the infrared radiation of the engine exhaust system was proposed based on the above model, and the performance of engine components and the overall engine was analyzed in terms of energy, exergy, mechanical efficiency, and thermal efficiency. Finally, the numerical simulations of the propulsion performance, thermodynamic efficiency and infrared characteristics of the adaptive cycle engine with cooling air were carried out under conditions of ground takeoff, subsonic cruise, and supersonic cruise. The simulation results show that the cooling air can effectively enhance engine performance and infrared stealth capabilities under various flight conditions. The ducted air extraction measures proposed in the paper could effectively improve the propulsion efficiency and stealth characteristics of the engine, providing important references for the development of more efficient aeroengine.

A method for analysing the dynamic response of a CWSLT under rainfall and earthquake

ABSTRACT In typical engineering applications of loess tunnels, rainfall has a significant influence on the loess mass of tunnels. In order to explore the influence of rainfall seepage on the tunnel dynamic response, this paper takes the common curved wall section loess tunnel (CWSLT) as an example, employs the finite element method (FEM), considers the effects of earthquakes and rainfall seepage, the CWSLT models are established and the shaking table test was carried out, the variation laws of stress, displacement, and acceleration of the CWSLT under different buried depths, rainfall amounts and earthquake types (near-field with pulse, near-field without pulse) are studied. The results show that with the increase of rainfall, the lining stress increases and the tensile stress in the middle of the inverted arch of the tunnel lining structure increases; Under different earthquakes, the maximum stress of the tunnel appears at the arch foot and the midpoint of the inverted arch; With the increase of buried depth, the settlement displacement of loess tunnel increases gradually. The above research results have important guiding significance for the design and construction of loess tunnels.

Prediction and optimization framework of shear strength of reinforced concrete flanged shear wall based on machine learning and non-dominated sorting genetic algorithm-II

Reinforced concrete (RC) flanged shear wall has good lateral strength and stiffness, which has been widely used in building structures. Due to the coupling effect of many factors such as wall section shape, shear span ratio, so the shear performance evaluation of flanged wall is still very limited. This paper proposed a prediction framework for the shear capacity of RC flanged shear walls. A database containing 14 input variables, 1 output variable and 153 samples was constructed to evaluate the prediction accuracy of 11 existing design methods. The Pearson coefficient was used to preliminarily analyze the correlation between variables. The grid search was used to optimize the hyperparameters of 4 machine learning models, and six statistical indicators ( R2, R, RMSE, SD, MAE, and MAPE) were used to comprehensively compare the prediction results of the ML models to determine the best model. On this basis, SHapley Additive exPlanations (SHAP) was used to enhance the interpretability of the prediction models, and the mechanism of the input variables on the shear capacity was quantified. A graphical user interface (GUI) was proposed to guide the engineering design. A multi-objective model (MOO) was established to analyze the trade-off between shear performance and cost, thereby determining the best optimal scheme. The results show that the prediction accuracy of the ML models is better than the existing design methods. The XGB model has the best prediction performance, with R2, R, RMSE are 0.99, 0.99, 118.96, respectively. The SHAP method can effectively enhance the interpretability of the ML models, and tw, lw and f ′c are the key parameters affecting the shear capacity of the flanged shear wall.

Managing the heat: In-Vessel Components.

The Spherical Tokamak for Energy Production (STEP) programme aims to deliver a first-of-a-kind fusion prototype powerplant (SPP). The SPP plasma places extreme heat, particle and structural loads onto the plasma-facing components (PFCs) of the divertor, limiters and inboard and outboard sections of the first wall. The PFCs must manage the heat and particle loads and wider powerplant requirements relating to safety, net power generation, tritium breeding and plant availability. To enable STEP PFC concepts to be identified that satisfy these wide-ranging requirements, an iterative design ('Decide & Iterate') methodology has been used to synchronize a prioritized set of decisions, within the fast-paced, iterative, whole plant concept design schedule. This paper details the 'Decide and Iterate' methodology and explains how it has enabled the identification of the SPP PFC concepts. These include innovative PFC solutions such as a helium-cooled discrete and panel limiter design to increase tritium breeding while providing sufficient coverage and enabling individual limiter replacement; the integration of the outboard first wall with the breeding zone to enhance fuel self-sufficiency and power generation; and the use of heavy water (D2O) within the inboard first wall and divertor PFCs to increase tritium breeding within the outboard breeding zone. This article is part of the theme issue 'Delivering Fusion Energy - The Spherical Tokamak for Energy Production (STEP)'.

Natural Capping Enhancing the Resilience of Earthen Heritage Under Rainfall Impacts

ABSTRACT Soft capping has proven effective in enhancing masonry ruins in humid regions. To-date, there are limited studies on the use of soft capping for earthen heritage in arid and semi-arid regions. Considering the diverse climatic conditions and the presence of vegetation on the Northern China earthen sites, there is an urgent need to study the effect of these vegetations on earthen heritage sites. As the plant species used in the previous studies are mainly based on artificial selection, we propose to use native plant species that are typically found in the study site and define the application of native plant species as ‘natural capping’. Taking the Ming dynasty Shanxi Great Wall sections as case study, four scale-down rammed earth test walls were subjected to rainfall tests under four patterns of rainfall once. Results showed that native plants excel in Northern climates. Under moderate rainfall, the moisture at the wall head of natural capping walls is nearly constant. However, when subjected to heavy and extreme rainfall, natural capping walls reduced inner wall moisture infiltration by 5.56%–7.52% and material loss by 58.24%–75.04%. Post-rainfall monitoring demonstrated that natural capping has sustainable benefits for temperature and moisture reduction in summer.

Penetrating wood foreign bodies (stob) of the coronary band in horses: 15 cases.

To retrospectively report the historical and clinical findings, diagnostics, treatment, and outcome of horses with penetrating wood foreign bodies (PWFBs) of the coronary band. 15 client-owned horses. Horses had varying degrees of lameness and soft tissue swelling of the coronary band and pastern region. A defect in the coronary band was identified, but the actual wood foreign body was not always readily visualized. Medical records of horses diagnosed with PWFBs of the coronary band between 2004 and 2023 were reviewed. Information retrieved from the medical records included history, signalment, diagnostics, treatment, and outcome. Thirteen of 15 horses that sustained a PWFB to the coronary band were participating in foxhunting. Penetrating wood foreign bodies occurred more frequently near the central axis or toe region (11/15) and more commonly in the forelimbs (11/15). Removal of PWFBs can be performed with the horse standing and sedated with regional anesthesia. Complete removal of the PWFB required partial removal of the adjacent hoof wall. Penetrating wood foreign bodies occurred in the coronary band and lodged distally in the hoof wall of horses. Foxhunting may be a risk factor for this type of injury. Penetrating wood foreign bodies occurred most commonly in the front feet, near the central axis of the coronary band. Complete removal of the PWFB required removing a section of the adjacent hoof wall. The prognosis for return to the previous level of activity following treatment was favorable.

Testing and design methods for high-strength aluminium alloy CHS members under combined axial compression and bending

The overall buckling behaviour of 7A04-T6 high-strength aluminium alloy circular hollow section (CHS) members subjected to combined compression and bending were investigated in this paper. Eight CHS beam-columns with two section wall thickness of 7.5 mm and 15 mm were tested, with the mechanical properties, initial geometric imperfections, failure modes and stability capacity of the specimens analyzed. The experimental findings were utilized in simulation analysis to verify the finite element (FE) model. Following this, a detailed parametric study including 486 numerical results was performed, with the variable parameters of section diameter to thickness ratio, member relative slenderness ratio and eccentricity. The experimental results and FE results were employed to assess the applicability of the existing design recommendations in European, Chinese, and American specifications for calculating the stability capacity of extruded 7A04-T6 high-strength aluminium alloy CHS beam-columns. The findings indicated that the three standards were not accurate in predicting the stability capacity of the CHS beam-columns, among which the European and American codified predictions were sometimes unsafe and much more discrete, and the Chinese code was too conservative by 35 %. Lastly, within the framework of the three standards evaluated in this paper, a approach of modifying the interaction buckling factors was proposed to improve the accuracy and consistency of the stability capacity predictions of 7A04-T6 high-strength aluminium alloy CHS beam-columns, which was also safe to some extent.