Search Results (176)

The Chacopampean Plain is a major physiographic unit in Argentina, bounded by the Colorado River to the south, the Sierras Pampeanas and Subandinas to the west, and the Paraná River, Río de la Plata Estuary, and the Argentine Sea to the east. Its subsurface preserves sediments from the Miocene marine transgression, while the surface hosts some of the country’s most productive soils. Two main geomorphological domains are recognized: fluvial systems dominated by alluvial megafans in the north, and aeolian systems characterized by loess accumulation and wind erosion in the south. The southern sector exhibits diverse landforms such as deflation basins, ridges, dune corridors, lunettes, and mantiform loess deposits. Despite their regional extent, the origin and chronology of many aeolian features remain poorly constrained, as previous studies have primarily focused on depositional units rather than wind-sculpted erosional features. This study integrates remote sensing data, field observations, and a synthesis of published chronometric and sedimentological information to characterize these aeolian landforms and elucidate their genesis. Our findings confirm wind as the dominant morphogenetic agent during Late Quaternary glacial stadials. These aeolian morphologies significantly influence the region’s hydrology, as many permanent and ephemeral water bodies occupy deflation basins or intermediate low-lying sectors prone to flooding under modern climatic conditions, which are considerably wetter than during their original formation. Full article

Pneumatic artificial muscles (PAMs) consist of an elastomeric bladder wrapped in a Kevlar braid. When inflated, PAMs expand radially and contract axially, producing large axial forces. PAMs are often utilized for their high specific work and specific power, as well as their ability to produce large axial displacements. Although the axial behavior of PAMs is well studied, the radial behavior has remained underutilized and is poorly understood. Modeling was performed using a force balance approach to capture the effects that bladder strain and applied axial load have on the anchoring force. Radial expansion testing was performed to validate the model. Force due to anchoring was recorded using force transducers attached to sections of aluminum pipe using an MTS servo-hydraulic testing machine. Data from the test were compared to the predicted anchoring force. Radial expansion in large-diameter (over 50.8 mm) PAMs was then used in worm-like robots to create anchoring forces that allow for a peristaltic wave, which creates locomotion through acrylic pipes. By radially expanding, the PAM presses itself into the pipe, creating an anchor point. The previously anchored PAM then deflates, which propels the robot forward. Modeling of the radial expansion forces and anchoring was necessary to determine the pressurization required for proper anchoring before slipping occurs due to the combined robot and payload weight. Full article

Improper car tire pressure affects dynamics, fuel economy, and driver safety. Current central tire inflation systems (CTISs) regulate tire pressure relative to its reference value. However, the current CTIS is limited in its automation, as the system requires the loading of present conditions and the manual input of terrain conditions. Therefore, the system lacks intelligent components which would increase its efficiency. Adding a terrain recognition feature to the current CTIS technology, the tire pressure management system (TPMS) described in this paper enhances the capability to adjust to the ideal tire pressure according to the terrain condition. In this study, we integrate a terrain recognition component which uses a convolutional neural network (CNN), specifically, ResNet-18, into the TPMS to classify and detect terrain conditions and apply the correct pressure level. A one-tire terrain-based TPMS model was developed through system integration. The system was tested under flat, uneven, and soft terrain conditions. The CNN model demonstrated 95% accuracy in classifying the chosen terrains, with demonstrated adaptability to nighttime environments. Inflation and deflation tests were conducted at varying speeds and terrains, and the results showed longer inflation times at higher pressure ranges, while deflation times remained consistent regardless of pressure range. A negligible impact on inflation and deflation speed was observed at speeds below 15 km/h. Instantaneous response time between the microcontrollers increases efficiency in the overall CTIS process. Full article

The Internet of Things (IoT) necessitates secure and lightweight firmware over-the-air (FOTA) update mechanisms for remote device management and timely mitigation of security vulnerabilities. This study introduces an FOTA update method to mitigate man-in-the-middle attacks in resource-constrained environments. The proposed method minimizes firmware file size and encryption overhead through a dual-XOR operation and DEFLATE compression, while enhancing security via multiple transmission channels. It improves performance in terms of latency, memory usage, and power consumption but also maintains security against brute-force attacks during MITM attacks. Full article

The aim of this work is to evaluate the influence of the surface deformations of an open inflatable wing section on aerodynamic performance and boundary layer separation phenomena. The inflation/deflation processes are allowed by an air intake placed on the bottom side of the model. Due to its low rigidity, non-contact measurements are required. Therefore, an infrared thermography technique was applied in order to detect local surface deformations and local separation phenomena. Additionally, the inflation and deflation of the whole wing were studied through an innovative approach, introduced by the authors, based on a piezoelectric sensor. It is important to note that open and closed wing sections exhibit very different aerodynamic behavior. For these reasons, both cases were investigated in the following research. The impact of deformation on the wing’s aerodynamic performance was assessed by means of wind tunnel tests. The inflatable wing presented lower lift and higher drag than the corresponding rigid wing due to the fabric’s deformations. Furthermore, the lift and moment coefficient curves were strongly related to the wing’s inflation. In particular, there was a change in the slope of the lift curve and a drop in the moment coefficient when the wing inflated. Lastly, the results provided evidence that a thermographic approach can be used to qualitatively detect local deformations of an inflatable wing and that a piezoelectric sensor can be used feasibly in detecting the inflation and deflation phases of a wing. Full article

Java Island, located in Indonesia, is the country’s main island, with a population of 150 million, more than half the population of the country. There are at least four big cities located on the island that have seen fast development in the last 30 years. The land subsidence (LS) issue caused by groundwater overexploitation, compaction, and geological setting, has been known on the island for more than 20 years. However, past studies have mostly focused on one particular important area, while the big picture of LS on the whole island is often overlooked. This study utilized Sentinel-1 Synthetic Aperture Radar (SAR) data from 2017 to 2023, analyzed using Small Baseline Subset (SBAS) interferometry, to map LS across Java Island. We used DEMNAS to eliminate the topographic signal. We found ten regions with a noticeable LS rate, affecting nearly 60 million people who reside in the LS zones, namely, Serang, Greater Jakarta, Cianjur, Bandung, Cirebon, Brebes and Tegal, Pekalongan, Greater Semarang, Surabaya, and Sidoardjo. The highest rates and the large coverage of LS were observed in Greater Jakarta (up to 150 mm/year), Bandung (200 mm/year), Semarang (160 mm/year), and Pekalongan (up to 110 mm/year). LS was also detected in smaller areas or districts, such as Serang, Cianjur, Cirebon, Brebes, Tegal, Surabaya, and Sidoarjo, with rates ranging from 60 to 140 mm/year. The two areas of Cianjur and Brebes, which have never been mentioned in previous studies, show LS rates of about 80 mm/year and 70 mm/year, respectively. The LS rate in all areas was shown to be linear over time, except in Pekalongan, which shows rate deflation after 2021. We also found that most affected regions are urban and industrial zones, indicating a strong correlation with anthropogenic activities. LS leads to widespread socioeconomic and environmental impacts, including damage to infrastructure, increased flooding, and reduced groundwater capacity. Full article

Coastal foredune blowout is a significant indicator of shoreline retreat, activation of backshore dune fields, and land desertification. Among current research on the terminal phase of coastal foredune blowouts, few studies explain blowouts’ morphological and airflow interaction mechanisms in the late stage through comprehensive field surveys and observations. In this study, the coastal blowout on the foredune at Tannanwan Beach, Pingtan Island, China, is investigated to explore the morphodynamics and evolutionary characteristics of blowout morphology. High-resolution RTK GPS technology and two-dimensional ultrasonic anemometers are utilized to repeatedly measure and observe the morphology of late-stage bowl blowouts. The results revealed that the following: (1) During the entire survey period, the bowl blowout is characterized by deepening erosion of the lateral walls and accretion in the deflation basin, with the maximum erosion depth on the east lateral wall reaching up to 3.99 m and the maximum accumulation height occurring in the front half of the deflation basin. (2) The wind direction and the morphology of the bowl blowout significantly impact the airflow characteristics within the blowout, and the airflow distribution within the blowout further affects the development of the blowout morphology. (3) The bowl blowout is in the late stage of its life cycle. Full article

Background and Objectives: Insufficient margin in lung cancer is associated with an increased locoregional recurrence rate. In pulmonary segmentectomy, two commonly used methods for identifying the intersegmental plane are inflation–deflation and indocyanine green dyeing. The aim of this study was to compare these two methods in terms of quality margins and to evaluate their superiority. Materials and Methods: A total of 63 patients who underwent segmentectomy via video-assisted thoracoscopic surgery (VATS) for pulmonary nodules and underwent preoperative planning with 3D modeling between October 2020 and February 2024 were included in this study. The location of the nodule and the distance to the intersegmental margins were virtually measured preoperatively using an open-source 3D modeling system. Patients were grouped according to the method of identifying the intersegmental margins. Group 1 included segmentectomies performed by the inflation–deflation method (n = 42), and Group 2 included segmentectomies performed by systemic indocyanine green (ICG) injection (n = 21). The area where the histopathological nodule was measured closest to the intersegmental margin was recorded. Values within (+/−10 mm) compared to the value measured in the three-dimensional model were considered successful. The obtained data were statistically compared between the groups. Results: There was no difference between the groups in terms of virtual and pathological margins. However, in terms of margin quality, the rate of deviation detected in the pathological margin compared to the measured virtual margin was significantly different between the groups (p = 0.04). Accordingly, the success rate was 64.3% in Group 1 and 90.5% in Group 2 (p = 0.05). In Group 1, the failure rate was highly against the adjacent parenchyma. There was no significant difference between the groups in the analysis of simple and complex segmentectomies. Conclusions: Intersegmental plane identification with indocyanine green increases the margin quality by defining resection margins closer to the virtual margins. In the inflation–deflation method, unnecessary parenchymal loss occurs due to disadvantages in identifying intersegmental margins. Full article

Deviation of an asset price from its fundamental value, commonly referred to as a price bubble, is a well-known phenomenon in financial markets. Mathematically, a bubble arises when the deflated price process transitions from a martingale to a strict local martingale. This paper explores price bubbles using the framework of optional semimartingale calculus within nonstandard probability spaces, where the underlying filtration is not necessarily right-continuous or complete. We present two formulations for financial markets with bubbles: one in which asset prices are modeled as càdlàg semimartingales and another where they are modeled as làdlàg semimartingales. In both models, we demonstrate that the formation and re-emergence of price bubbles are intrinsically tied to the lack of right continuity in the underlying filtration. These theoretical findings are illustrated with practical examples, offering novel insights into bubble dynamics that hold significance for both academics and practitioners in the field of mathematical finance. Full article

Background: The aim of this study was to evaluate blood pressure (BP) difference between cuff inflation and deflation and to investigate whether hypertension grade and patients’ characteristics could be influential. Methods: We selected 328 asymptomatic patients, 219 with mild systolic/diastolic hypertension, 75 with moderate systolic/diastolic hypertension and 34 with severe systolic/diastolic hypertension. Results: Hypertension grade was a determinant of the difference between systolic/diastolic BP during cuff inflation and deflation; the difference was progressively and significantly higher from mild to moderate to severe hypertension (1.80 ± 1.03/1.21 ± 0.56 vs. 5.32 ± 1.09/3.04 ± 0.81 vs. 9.74 ± 1.46/4.88 ± 0.73 mmHg, respectively (all differences were significant). Age, gender, body mass index, smoking habits and laboratory parameters were not associated with BP differences. The observed differences led to a reclassification of 24% of patients with moderate and 32% of patients with severe hypertension to a lower grade, but all were classified as hypertensive patients during cuff inflation. Conclusions: Hypertension grade influences the difference in systolic/diastolic BP during cuff inflation and deflation. This difference leads to a reclassification of hypertension grade during cuff inflation within the hypertensive range but does not influence the definition of hypertensive status. Future studies are needed to confirm whether the differences in systolic/diastolic BP between cuff inflation and deflation are due to BP increases induced by sympathetic activation, as well as a potential different behavior of the brachial artery during closing or opening, or both. Full article

We extend the 3D Lattice Boltzmann method with a deformable boundary (LBM-DB) for the computations of the full-volume colonic flow of the Newtonian fluid driven by the peristaltic segmented circular contractions which obey the three-step “intestinal law”: (i) deflation, (ii) inflation, and (iii) elastic relaxation. The key point is that the LBM-DB accurately prescribes a curved deforming surface on the regular computational grid through precise and compact Dirichlet velocity schemes, without the need to recover for an adaptive boundary mesh or surface remesh, and without constraint of fluid volume conservation. The population “refill” of “fresh” fluid nodes, including sharp corners, is reformulated with the improved reconstruction algorithms by combining bulk and advanced boundary LBM steps with a local sub-iterative collision update. The efficient parallel LBM-DB simulations in silico then extend the physical experiments performed in vitro on the Dynamic Colon Model (DCM, 2020) to highly occlusive contractile waves. The motility scenarios are modeled both in a cylindrical tube and in a new geometry of “parabolic” transverse shape, which mimics the dynamics of realistic triangular lumen aperture. We examine the role of cross-sectional shape, motility pattern, occlusion scenario, peristaltic wave speed, elasticity effect, kinematic viscosity, inlet/outlet conditions and numerical compressibility on the temporal localization of pressure and velocity oscillations, and especially the ratio of retrograde vs antegrade velocity amplitudes, in relation to the major contractile events. The developed numerical approach could contribute to a better understanding of the intestinal physiology and pathology due to a possibility of its straightforward extension to the non-Newtonian chyme rheology and anatomical geometry. Full article

Pneumatic artificial muscles (PAMs) are flexible actuators that can be contracted or expanded by applying air pressure. They are used in robotics, prosthetics, and other applications requiring flexible and compliant actuation. PAMs are basically designed to mimic the function of biological muscles, providing a high force-to-weight ratio and smooth, lifelike movement. Inflation and deflation of these muscles can be controlled rapidly, allowing for fast actuation. In this work, a continuum mechanics-based model is developed to predict the output parameters of PAMs, like actuation force. Comparison of the model results with experimental data shows that the model efficiently predicts the mechanical behaviour of PAMs. Using the actuation force–air pressure–contraction relation provided by the proposed mechanical model, a dynamic model is derived for a multi-link PAM-actuated robot manipulator. An adaptive fixed-time fast terminal sliding mode control is proposed to track the desired joint position trajectories despite the model uncertainties and external disturbances with unknown magnitude bounds. Furthermore, the performance of the proposed controller is compared with an adaptive backstepping fast terminal sliding mode controller through numerical simulations. The simulations show faster convergence and more precise tracking for the proposed controller. Full article

Count data often exhibit discrepancies in the frequencies of zeros, which commonly occur across various application domains. These data may include excess zeros (zero inflation) or, less frequently, a scarcity of zeros (zero deflation). In regression models, both situations can arise at different levels of covariates. The zero-modified power series regression model provides an effective framework for modeling such count data, as it does not require prior knowledge of the type of zero modification, whether zero inflation or zero deflation, and can accommodate overdispersion, equidispersion, or underdispersion present in the data. This paper proposes a Bayesian estimation procedure based on the stochastic gradient Hamiltonian Monte Carlo algorithm, effectively addressing many challenges associated with estimating the model parameters. Additionally, we introduce a measure of Bayesian efficiency to evaluate the impact of prior information on parameter estimation. The practical utility of the proposed method is demonstrated through both simulated and real data across different types of zero modification. Full article

Background/Objectives: The nine-step inflation/deflation tympanometric Eustachian tube function test (commonly referred to as the nine-step test) is a widely utilized method for evaluating Eustachian tube function (ETF). This study aimed to establish normative values for the nine-step test to facilitate the diagnosis of Eustachian tube dysfunction (ETD). Methods: A total of 160 adults, including 70 healthy volunteers and 90 patients with chronic rhinosinusitis (CRS), were recruited for this study. Participants were further categorized into “fair ETF” and “poor ETF” groups based on their scores on the Eustachian Tube Dysfunction Questionnaire (ETDQ-7). Eustachian tube function was assessed using both the nine-step test and the ETDQ-7. The diagnostic accuracy of the maximal peak pressure difference (MPD) from the nine-step test was evaluated, using an ETDQ-7 score of ≥14 as the reference standard. Discriminative ability was analyzed using receiver operating characteristic (ROC) curves. Results: An MPD value of ≤4 yielded an area under the ROC curve (AUC) of 0.619, indicating moderate discriminative ability in the Taiwanese population. The median MPD value on the nine-step test was 9.5 (interquartile range [IQR]: 4.5–14.0) in participants with an ETDQ-7 score of <14, compared to a median MPD value of 7.5 (IQR: 2.5–12.0) in those with an ETDQ-7 score of ≥14 (p = 0.033). This finding suggests a potential association between MPD values and ETDQ-7 scores. Conclusions: This study identified an MPD value of 4 as a normative cutoff for screening ETD in a Taiwanese population. However, the diagnostic discriminative power of this parameter was moderate. Full article

This article is devoted to the study of the Quaternary aeolian sands of the boreal zone of north Asia. Using the example of the study reference sections of the Selenga Dauria (Western Transbaikalia), it was established that the activation of aeolian processes is determined by the complex interaction of natural and anthropogenic factors. Natural factors include neotectonic movements; wide distribution of alluvial and lacustrine-alluvial deposits; a sharply continental semi-arid climate; and forest-steppe and steppe vegetation. Among the anthropogenic factors, the leading ones are deforestation, plowing of land and construction of new settlements, roads and other line structures. The obtained radiocarbon dating of buried soils and coal from ancient fire pits indicates the activation of aeolian processes during the Holocene. The main sources for aeolian transport (winnowing) are sands located in the areas of river and lake beaches, floodplains and river terraces. Almost all aeolian sands of the boreal zone were formed as a result of short-range wind transport. They form mini-deserts unfixed by vegetation, with active aeolian processes, dunes, barkhans and deflationary basins. Aeolian swells and blowout basins characterize aeolian landscapes weakly fixed by vegetation. It is noted that aeolian deposits of the boreal zone of north Asia, in contrast to similar sands of the subtropical and tropic zones, consist of coarser-grained material. Medium- and fine-grained sands dominate their composition, which is polymineral and well-sorted. In subtropical and tropical deserts, they are predominantly monomineral, fine and fine-grained. At the same time, mainly minerals that are unstable to weathering (feldspars, plagioclases, pyroxenes and amphiboles) represent the mineralogical composition of the studied aeolian sands. Weathering-resistant minerals dominate the sands of classical deserts: quartz, leucoxene, ilmenite, epidote, zircon, garnets, tourmaline, rutile and others. Modern aeolian landscapes are a unique natural formation for the boreal zone of north Asia and can be successfully used for the development of ecotourism. Full article