Floor Shape Research Articles

Effect of Y-shaped Nasal Columella Made of Autologous Cartilage in Secondary Nasal Deformity after Cleft Lip Surgery.

Due to the diversity and complexity of tissues involved in secondary nasal deformities following unilateral cleft lip, secondary nasal deformity correction surgeries are challenging and often yield unsatisfactory results, posing a difficult problem for plastic surgeons. Autologous cartilage, with its low sculpting difficulty, minimal absorption, and stable tissue compatibility, is considered the optimal material for reconstructing the columella, nasal tip, and alar. This study analyzed the clinical outcomes of using autologous cartilage to create a Y-shaped columella to correct secondary nasal deformities after cleft lip surgery. In this retrospective study, 75 patients with secondary nasal deformity after unilateral cleft lip surgery were treated from January 2018 to December 2023. Appropriate costal cartilage, auricular cartilage, and iliac crest cartilage were fashioned into Y-shaped stents and implanted into the nasal columella of the patients to strengthen the tip cartilage. The free alar cartilage was sutured and fixed with a Y-shaped bracket. The wound healing rate, subjective satisfaction evaluation, and complications were analyzed. The nasal appearance, nasal deformity classification, and objective indices of healthy and affected nasal sides, function, and quality of life were compared before and after the operation. All patients healed well during the first stage without related complications, and the average incision healing time was 5.16 ± 1.37 days. The scores of nasal tip position, nasal tip shape, nostril shape, nasal dorsum shape, and nasal floor shape at 6 months post-operation were significantly lower compared to pre-operation (p < 0.001). The grade of nasal deformity at 6 months post-operation was lower than the pre-operation (p < 0.001). Pre-operation, the nasal base and nasal width of the affected side were higher than those of the healthy side, while the nasal columellar and nostril height were lower (p < 0.001). At 6 months post-operation, the nasal base and nasal width decreased, and the nasal columellar and nostril height increased (p < 0.001), with no significant difference between the two sides (p > 0.05). The nasal obstruction symptom evaluation (NOSE) and Functional Rhinoplasty Outcome Inventory-17 (FROI-17) scores at 6 months post-operation were significantly lower than pre-operation, while the rhinoplasty outcome evaluation (ROE) score was higher (p < 0.001). The total patient satisfaction was 97.33% (73/75). Y-shaped nasal columella made of autologous cartilage can effectively correct secondary nasal deformity after cleft lip surgery, improve nasal alar collapse, lengthen nasal columella, elevate nasal end, enhance the quality of life, nasal appearance, and nasal ventilation function of patients, with high satisfaction and few complications.

Dynamical Controls on Bottom Water Transport and Transformation across the Antarctic Circumpolar Current

Abstract The export of Antarctic Bottom Water (AABW) supplies the bottom cell of the global overturning circulation and plays a key role in regulating climate. This AABW outflow must cross, and is therefore mediated by, the Antarctic Circumpolar Current (ACC). Previous studies present widely varying conceptions of the role of the ACC in directing AABW across the Southern Ocean, suggesting either that AABW may be zonally recirculated by the ACC, or that AABW may flow northward within deep western boundary currents (DWBC) against bathymetry. In this study the authors investigate how the forcing and geometry of the ACC influences the transport and transformation of AABW using a suite of process-oriented model simulations. The model exhibits a strong dependence on the elevation of bathymetry relative to AABW layer thickness: higher meridional ridges suppress zonal AABW exchange, increase the strength of flow in the DWBC, and reduce the meridional variation in AABW density across the ACC. Furthermore, the transport and transformation vary with density within the AABW layer, with denser varieties of AABW being less efficiently transported between basins. These findings indicate that changes in the thickness of the AABW layer, for example, due to changes in Antarctic shelf processes, and tectonic changes in the sea floor shape may alter the pathways and transformation of AABW across the ACC. Significance Statement The ocean plays an outsized role in the movement of heat and trace gases around Earth, and the northward export of dense Antarctic Bottom Water is a crucial component of this climate-regulating process. This study aims to understand what sets the pathways of Antarctic Bottom Water as it travels northward across the Antarctic Circumpolar Current, and thus what controls its partitioning between the Atlantic, Indian, and Pacific basins. Our results highlight the importance of seafloor elevation relative to the thickness of the Antarctic Bottom Water layer for directing the flow northward versus between basins. This study motivates future investigation of long-term changes in Antarctic Bottom Water properties and their consequences for its global distribution.

Feasibility of achieving net-zero energy performance in high-rise buildings using solar energy

As part of a broad strategy to reach net-zero greenhouse gas emissions and limit global warming, many countries are requiring all new buildings to have net-zero energy use. This requires that on-site energy use not exceed on-site generation of renewable energy (taken here to be solar energy), or equivalently, that the building Energy Use Intensity (EUI, kWh/m2a) not exceed the supply of on-site solar energy (electricity and heat) per m2 of floor area per year. On this basis, we find that achieving net-zero energy performance in an archetype 40-story square building in 16 different cities of North America requires EUI of 17–24 kWh/m2a using PV panels, and 19–28 kWh/m2a using PVT collectors. Changing building orientation to a non-square floor shape can improve maximum permitted EUI by up to 50% in PV and 60% in PVT case. Conversely, the best-performing residential and commercial buildings have EUIs of 50–75 kWh/m2a. Only if building heights are limited to 5–10 floors does the available solar energy, and thus the permitted EUI, reach 50–75 kWh/m2a. Therefore, we recommend that policymakers not require high-rise buildings to be net-zero energy, unless they are prepared to limit building heights to 5–10 floors.

漢江 下流域 청동기시대 전기 住居의 變異 이해 - 金浦ㆍ仁川지역 유적을 중심으로 -

It has been suggested that the Early Bronze Age rectangular dwellings were also the result of the family composition of society at the time, and that the morphological variation was due to the family developmental cycle. In addition, multiple rectangular(unit) dwellings are connected in parallel, and the estimation that rectangular unit dwellings are residential spaces for nuclear families is also widespread. However, many researchers tend to interpret the relationship between long rectangular dwellings and rectangular dwellings coexisting in one site as a fixed cultural entity by judging that the long to short axes ratio reflects time. This perspective has raised problems that hinder the understanding of various factors on housing variation-changes in housing size due to family development, the use of housing (renewal, expansion, renovation), and disposal. To overcome this problem, this paper examined the possibility that the perception of household development cycles will highlight the dynamic aspects of the Bronze Age housing pattern in the Lower Reaches of Hangang River by comparing it with an archaeological explanatory model that can connect family and household changes. In the end, it is difficult to dynamically explain the early Bronze Age residential pattern of the Lower Reaches of Hangang River in the houses of different floor shapes, which focuses on the floor plan of the residence in a situation where overlapping patterns or absolute solidarity between dwellings are ambiguous. Therefore, it would be reasonable to assume the functional aspect of the change in dwelling structure according to the development of the family rather than grasping the difference in the shape of the residential floor shapes as a fixed cultural entity.

Tuned tandem mass dampers-inerters for suppressing vortex-induced vibration of super-tall buildings

Modern super-tall buildings with rectangular floor shapes are vulnerable to significant vibrations due to the vortex shedding effect formed around structural edges. Tuned tandem mass dampers-inerters (TTMDI) is extended in this study to suppress vortex-induced responses of super tall buildings for occupant comforts. The optimal TTMDI tuning problem for a 400 m super tall building exposed to crosswind loads is solved through frequency-domain analysis. Meanwhile, the control performance of TTMDI is explored and contrasted with that of the tuned mass damper (TMD), tuned tandem mass dampers (TTMD) and tuned mass damper‐inerter (TMDI) from various perspectives. A crosswind-resistant design framework of the TTMDI equipped super-tall building system is then devised to meet comfort requirements. Finally, results are further assessed in the time -domain using a virtual real time hybrid simulation (VRTHS) system based on the proposed hybrid model predictive controller. It is found that there are several optimal inertance coefficient redistribution points (i.e. R points) in the design process and the R points have a great impact on the optimal internal structure of TTMDI. Results clearly demonstrate that TTMDI has better effectiveness and robustness than TMD, TTMD, and TMDI. Moreover, the total demand for total damping coefficients of TTMDI is significantly smaller than TMDI after the R points, indicating that it is easier to implement in engineering practices.

Research on Anatomy of the Pulp Chamber Floor of the Maxillary Second Permanent Molar in CBCT

Objective: The objective of this study was to examine the pulp chamber floor anatomy of the maxillary second permanent molar in Chinese individuals by using Cone-Beam Computed Tomography (CBCT). These data may facilitate endodontic treatment success. Methodology: A total of 2505 CBCT images of maxillary second permanent molars were studied to evaluate the shape of the pulp chamber floor, the types of developmental root fusion lines (DRFLs), the number of canal orifices and their possible relationships. Results: Three pulp chamber floor shapes were identified: triangular (50.3%), rhomboid (34.3%) and oval (15.4%). The shape of the DRFLs and the number of canal orifices on the pulp chamber floor were variable. The frequency of non branching DRFLs was 63.8%, followed by branching DRFLs (33.6%). The I-shaped DRFL group had more variations in the number and location of canal orifices. Conclusion: The anatomy of the pulp chamber floor of the maxillary second permanent molar in Chinese individuals is diverse. Knowledge of variations in pulp chamber shape, types of DRFLs and canal orifice number of the maxillary second permanent molar can help reduce the risk of missing root canals in endodontic treatment.

The variation in shape and thickness of the pelvic floor musculature in males and females: a geometric-morphometric analysis

Introduction and hypothesisIn women, the risk of pelvic floor prolapse is known to be associated with age and parity. Different studies suggested that it is also related to pelvic dimensions, e.g. biomechanical modelling showed that a larger pelvic canal results in higher values of displacement, stress and strain in the pelvic floor muscles, which can increase the risk of pelvic floor disorders. To better understand the multiple factors contributing to pelvic floor disorders, we assessed how age, body weight, body height, parity (in women), pelvic canal size and overall muscle development affected pelvic floor geometry.MethodsA comprehensive geometric morphometric analysis of variation in pelvic floor muscle shape was conducted based on a dense set of 3D landmarks measured on CT scans in a cohort of 49 deceased men and 52 deceased women. The multivariate association between biological variables (parity, dimensions of the true pelvis, age, body weight, height) and pelvic floor muscle morphology was explored by reduced rank regression in both sexes.ResultsIn women, advanced age, high body weight relative to body height and a large pelvic canal were associated with a deeper pelvic floor. Surprisingly, parity did not have any strong association with overall pelvic floor shape. In men, high body weight was associated with a deep pelvic floor. Age had little effect on male pelvic floor shape, except for the thickness of the ischiocavernosus muscle, which reduced with age. ConclusionThese results suggest that age, relative body weight and the size of the pelvic canal contribute to the risk of female pelvic floor disorders via their effect on pelvic floor shape, independently of birth-related factors such as injury and avulsion of pelvic floor muscles.

Measuring dimensional and morphological heat alterations of dismemberment-related toolmarks with an optical roughness metre.

This experimental study provides a further understanding of the post-burning nature of sharp force trauma. The main objective is to analyse the distortion that fire may inflict on the length, width, roughness, and floor shape morphology of toolmarks induced by four different implements. To this end, four fresh juvenile pig long bones were cut with a bread knife, a serrated knife, a butcher machete, and a saw. A total of 120 toolmarks were induced and the bone samples were thus burnt in a chamber furnace. The lesions were analysed with a 3D optical surface roughness metre before and after the burning process. Afterwards, descriptive statistics and correlation tests (Student's t-test and analysis of variance) were performed. The results show that fire exposure can distort the signatures of sharp force trauma, but they remain recognisable and identifiable. The length decreased in size and the roughness increased in a consistent manner. The width did not vary for the saw, serrated knife, or machete toolmarks, while the bread knife lesions slightly shrunk. The floor shape morphology varied after burning, and this change became more noticeable for the three knives. It was also observed that the metrics of the serrated knife and machete cut marks showed no significant variations. Our results demonstrate that there is a variation in the toolmark characteristics after burning. This distortion is dependent on multiple factors that influence their dimensional and morphological changes, and the preservation of class features is directly reliant upon the weapon employed, the trauma caused, and the burning process conditions.

A Self-Powered Basketball Training Sensor Based on Triboelectric Nanogenerator

During the basketball training for beginner children, sensors are needed to count the number of times the basketball hits the target area in a certain period of time to evaluate the training effect. This study proposes a self-powered basketball training sensor, based on a triboelectric nanogenerator. The designed sensor with a rectangular floor shape will output a pulse signal with the same frequency as the basketball impact to achieve the measurement function through the mutual contact of the internal copper (Cu) and polytetrafluoroethylene (PTFE). Test results show that the working frequency of the sensor is 0 to 5 Hz, the working environment temperature should be less than 75 °C, the working environment humidity should be less than 95%, and which has high reliability. Further tests show that the maximum output voltage, current, and power of the sensor can reach about 52 V, 4 uA, and 26.5 uW with a 10 MΩ resistance in series, respectively, and the output power can light up 12 light-emitting diode (LED) lights in real-time. Compared with the traditional statistical method of manual observation, the sensor can automatically count data in a self-powered manner, and also can light up the LED lights in real-time as an indicator of whether the basketball impacts the target area, to remind beginner children in real-time.

Structural floor shape efficiency of circular and square high rise structure towards lateral loadings

The building shape is one of the most important considerations in the conceptual stage of building design. Since the building shape determines the size and the orientation of the exterior envelope exposed to the outdoor environment, it can affect building performance in many aspects: energy efficiency, cost and aesthetics. The shape and exterior structure of a house play major roles in determining its energy efficiency and the comfort of residents. The shape is comprised of the building’s height, width, and depth-also known as the footprint. The determination of the structural shape of a high-rise building would preferably involve only the selection and arrangement of the major structural element to resist most efficiently the various combinations of gravity and horizontal loading. Based on the above considerations, this study focuses on the responses by analysing the effects of the lateral loads on two 20 storied high rise structures having edge supported floor systems each of which one with square floor shape and another with circular floor and finally, presents a comparative result.

Structural floor shape efficiency of circular and square high rise structure towards lateral loadings

Structural floor shape efficiency of circular and square high rise structure towards lateral loadings

Statistical shape modeling of the pelvic floor to evaluate women with obstructed defecation symptoms

Obstructed defecation (OD) is common and may be related to compromised pelvic floor integrity. Magnetic resonance (MR) defecography and statistical shape modeling were used to define pelvic floor shape variations, hypothesizing that State (rest vs peak evacuation) and Group (control vs case) would significantly influence shape. 16 women underwent MR defecography (9 cases vs 7 controls). Midsagittal, 2D pelvic floors were segmented and aligned by corresponding points. Principal component scores were compared using a Two-Way Mixed MANOVA. Three modes described differences between State (p < 0.001) and Group (p = 0.023). The pelvic floor shape differed significantly between women with and without OD and during evacuation.

Pelvic floor shape variations during pregnancy and after vaginal delivery

Background and objectiveStrong evidence suggests that pelvic soft tissues soften during pregnancy to facilitate vaginal delivery while protecting against maternal birth injury. We hypothesized that these adaptations likely result in changes to the shape of the pelvic floor. Thus, this study aimed to compare midsagittal pelvic floor shapes from MRIs of nulliparous, gravid, and vaginally parous women using statistical shape modeling. MethodsA retrospective study of 22 nulliparous, 29 gravid (vaginally nulliparous), and 18 vaginally parous women who underwent pelvic MRI was performed. The pelvic floor was segmented from pubic symphysis to coccyx as a 2D polyline in the midsagittal plane. Once corresponding landmarks were computed and the variances between them determined by principal component analysis, the principal component scores were calculated for modes that explained variance greater than noise. These became the dependent variables in a MANOVA with univariate ANOVAs, linear regressions, and Benjamini-Hochberg corrections post hoc. Two initial statistical shape analyses were conducted to analyze differences based on gestational age (1st/2nd vs 3rd trimester) and vaginal parity (VP1 vs VP2-4). There were significant differences based on gestational age, but not vaginal parity. Thus, the final statistical shape analysis evaluated pelvic floor shapes of nulliparous, 3rd trimester gravid, and all vaginally parous subjects. ResultsIn the final analysis, six modes described variance—a measure of shape variability—greater than noise. Groups differed significantly for modes 1, 2, and 4 (p < 0.001, p = 0.021, and p = 0.015, respectively) and only differed between the nulliparous and gravid groups (p < 0.001, p = 0.018, and p = 0.012, respectively). Anatomically, these modes described levator plate relaxation and level III support protrusion in gravid compared to nulliparous subjects while the parous group straddled the other two. ConclusionsThe shape of the pelvic floor changes significantly during pregnancy and some of those changes are present after vaginal delivery. The fact that the nulliparous and gravid groups differ while the parous is similar to both suggests that some parous women regain their nulliparous shape after pregnancy and delivery while others do not. This indicates that remodeling during pregnancy and/or injury during vaginal delivery can have lasting effects on the pelvic floor.

Effect of Floor Shape Optimization on Energy Consumption for U-Shaped Office Buildings in the Hot-Summer and Cold-Winter Area of China

This paper explored the effects of the side proportion of building floor shape on building energy consumption. It is based on the analysis of regression models that were developed in the present study. The simplified building models can be used to conduct a parametric study to investigate the effect of building plane shape parameters on total heating and cooling load. DesignBuilder was used to build and simulate individual building configuration. Energy consumption simulations for forty-eight U-shaped buildings with different plane layouts were performed to create a comprehensive dataset covering general ranges of side proportions of U-shaped buildings and building orientations. Statistical analysis was performed using MATLAB to develop a set of regression equations predicting energy consumption and optimizing floor shapes. Furthermore, perimeter-area ratio (PAR), width ratio, and depth ratio were considered as three factors to characterize the quantitative relationship between floor shape and energy consumption. It is envisioned that the binary quadratic polynomial regression models, visualized as a smooth surface in space and mapped to a vortex image on the plane, can be used to estimate the energy consumption in the early stages of the design when different building schemes and design concepts are being considered.

Optimization of diagrid geometry based on the desirability function approach

Abstract Diagrids represent one of the emerging structural systems employed worldwide for the construction of high-rise buildings. Their potential relies on the peculiar architectural effect and their great lateral stiffness. Because of the modular nature of the diagrid triangular element, optimization processes are usually carried out to assess the best arrangement of the external diagonals in order to enhance the structural performance while using the lowest amount of structural material. In this contribution, we make use for the first time of the desirability function approach to investigate the optimal geometry of the dia-grid system. A 168-meter tall building, with four different floor shapes, is analyzed, and the inclination of the external diagonals is varied between 35° and 84°. The desirability function approach is applied to find the most desirable geometry to limit both the lateral and torsional deformability, the amount of employed material as well as the construction complexity of the building. A sensitivity analysis is also carried out to investigate the influence of the individual desirability weight on the obtained optimal geometry. The effect of the building height is finally evaluated, through the investigation of sets of 124-, 210- and 252-meter tall diagrid structures.

Improvement in early urinary continence recovery after robotic-assisted radical prostatectomy based on postoperative pelvic anatomic features: a retrospective review

BackgroundWe investigated the impact of postoperative membranous urethral length and other anatomic characteristics of the pelvic floor shape as measured by magnetic resonance imaging on the improvement in continence following robotic-assisted radical prostatectomy.MethodsWe retrospectively reviewed data from 73 patients who underwent postoperative prostate magnetic resonance imaging following robotic-assisted radical prostatectomy between 2013 and 2018. Patient demographics; pre-, peri-, and post-operative parameters; and pelvic anatomic features on magnetic resonance imaging were reviewed. Patients who used no urinary incontinence pads or pads for protection were considered to have achieved complete continence.ResultsUrinary continence was restored in 27.4, 53.4, 68.5, and 84.9% of patients at 1, 3, 6, and 12 months after robotic-assisted radical prostatectomy, respectively. When patients were divided into early and late continence groups based on urinary continence at 3 months after robotic-assisted radical prostatectomy, no significantly different clinical characteristics or surgical outcomes were found. However, the mean membranous urethral length (18.5 mm for the early continence group vs. 16.9 mm for the late continence group), levator muscle width (7.1 vs. 6.5 mm, respectively), and bladder neck width on the trigone side (7.2 mm vs. 5.4 mm, respectively) were significantly different between groups (all p < 0.05). Multivariate logistic regression analysis showed that membranous urethral length (odds ratio, 1.227; 95% confidence interval, 1.011–1.489; p = 0.038) and bladder neck width (odds ratio, 1.585; 95% confidence interval, 1.050–2.393; p = 0.028) were associated with the period of early urinary continence.ConclusionsPostoperative membranous urethral length and bladder neck width were significantly associated with early urinary continence recovery after robotic-assisted radical prostatectomy. It is highly recommended that surgeons focus on preserving the membranous urethral length and increasing the bladder neck width on the trigone side during surgery to achieve optimal continence outcomes after robotic-assisted radical prostatectomy.

Quantifying the protective capacity of mangroves from storm surges in coastal Bangladesh.

Mangroves are an important ecosystem-based protection against cyclonic storm surge. As the surge moves through the mangrove forest, the tree roots, trunks, and leaves obstruct the flow of water. Damage to adjacent coastal lands is attenuated mainly by reducing (i) surge height, which determines the area and depth of inundation and (ii) water flow velocity. But the extent of mangrove protection depends on the density of tree plantings and the diameter of trunks and roots, along with an array of other forest characteristics (e.g., floor shape, bathymetry, spectral features of waves, and tidal stage at which waves enter the forest). Making efficient use of mangroves’ protective capacity has been hindered by a lack of location-specific information. This study helps to fill that gap by estimating reduction in storm surge height and water flow velocity from mangroves at selected sites in cyclone-prone, coastal Bangladesh. A hydrodynamic model for the Bay of Bengal, based on the MIKE21FM system, was run multiple times to simulate the surge of cyclone Sidr (2007) at the Barisal coast. Estimates of surge height and water flow velocity were recorded first without mangroves and then with mangroves of various forest widths and planting densities, including specific information on local topography, bathymetry, and Manning’s coefficients estimated from species’ root and trunk systems. The results show a significant reduction in water flow velocity (29–92%) and a modest reduction in surge height (4–16.5 cm). These findings suggest that healthy mangroves can contribute to significant savings in rehabilitation and maintenance costs by protecting embankments from breaching, toe-erosion, and other damage.

Ascending and Descending in Virtual Reality: Simple and Safe System Using Passive Haptics.

This paper presents a novel interactive system that provides users with virtual reality (VR) experiences, wherein users feel as if they are ascending/descending stairs through passive haptic feedback. The passive haptic stimuli are provided by small bumps under the feet of users; these stimuli are provided to represent the edges of the stairs in the virtual environment. The visual stimuli of the stairs and shoes, provided by head-mounted displays, evoke a visuo-haptic interaction that modifies a user's perception of the floor shape. Our system enables users to experience all types of stairs, such as half-turn and spiral stairs, in a VR setting. We conducted a preliminary user study and two experiments to evaluate the proposed technique. The preliminary user study investigated the effectiveness of the basic idea associated with the proposed technique for the case of a user ascending stairs. The results demonstrated that the passive haptic feedback produced by the small bumps enhanced the user's feeling of presence and sense of ascending. We subsequently performed an experiment to investigate an improved viewpoint manipulation method and the interaction of the manipulation and haptics for both the ascending and descending cases. The experimental results demonstrated that the participants had a feeling of presence and felt a steep stair gradient under the condition of haptic feedback and viewpoint manipulation based on the characteristics of actual stair walking data. However, these results also indicated that the proposed system may not be as effective in providing a sense of descending stairs without an optimization of the haptic stimuli. We then redesigned the shape of the small bumps, and evaluated the design in a second experiment. The results indicated that the best shape to present haptic stimuli is a right triangle cross section in both the ascending and descending cases. Although it is necessary to install small protrusions in the determined direction, by using this optimized shape the users feeling of presence of the stairs and the sensation of walking up and down was enhanced.

Nonlinear analysis of water-soil-barrage floor interaction

Fluid - Structure Interaction (FSI) and Soil-Structure Interaction (SSI) are mostly considered in the non-linear analysis of water-soil-barrage floor interaction. A three dimensional (3D) - section of a barrage is selected and modelled via ANSY 15.0. The ogge barrage floor shape has been taken as a case study of analysis. The non-linear analysis of the structure model is developed through selecting suitable available elements in ANSYS which are related to the case under study and is compared with linear analysis. The results of the analysis are obtained by suggesting different characteristics of concrete, soil, and rock materials as a parametric study. Both closed barrage and in operation are the cases have been considered in analysis. It is concluded from this study that ANSYS/APDL is adequate tool to simulate and analysis the problem that need sufficient experiences to select suitable available elements to get the acceptable results. It is also concluded that the deformation in barrage floor has little difference by (6%) in linear and non-linear analysis in case of no operation. While this deformation in non-linear analysis with operation condition is less by (13%) than of no operation case. The non-linear deformation of barrage floor is more effective by change of density of barrage concrete itself, modulus of elasticity and yield stress of both soil and rock foundation materials, while no sensitive effect of change of Poisson’s ratio on the deformation. The maximum seepage flow at exit point downstream barrage floor with upstream and downstream piles is lesser by (67.40%) than without pile. In the view of stability, it is concluded that the barrage floor is already safe in exist gradient and piping problems with or without piles.

Three-dimensional investigation of the effects of regular seafloor geometry on low frequency sound propagation using parabolic equations

Underwater propagation of sound is constrained by multiple physical factors among which the physical boundaries of the underwater world add to the complexity of the numerical modeling of this phenomenon. The present study investigates the effects of the sea floor shapes on transmission loss of sound in low frequencies. To accomplish this task, a computer code is developed based on three-dimensional parabolic equations using implicit finite difference approach. This code is validated by two sets of published data, ensuring the high accuracy of the code in low frequency modeling. Furthermore, as extreme representatives of the arbitrary and complex sea floor shapes, three geometries of hemisphere (for rounded slopes), cubic and cone shapes (for the rocky sea floors) made of granite are assumed in tandem 3 × 3 arrangements with different heights and dimensions. For better understanding of three-dimensional effects of these obstacles on sound propagation, the results are extracted in three directions of 30°, 60° and 90°. The conducted parametric studies show that rounded and conical sea beds have the highest transmission loss which is not significantly affected by the arrangement of the obstacles. On the other hand, the cubic obstacles have a low mean transmission loss, which is highly affected by the arrangement of the obstacles. It should be pointed out that in some arrangements of the cubic obstacles, even sound intensification occurs. Moreover, it is shown that the effect of obstacle heights on the average transmission loss is highly dependent on the direction of the propagation. It has been demonstrated that maximum value of local transmission loss occurs for the cubic arrangements, when the heights of cubic arrangements are about 2, 1, and 4 times of the wave length in the directions of 30°, 60° and 90°, respectively. Study of the heights of the seamounts indicates that variation of the heights does not have significant effect on the average of transmission loss. The results provided in the present study establish a preliminary step towards the acoustical modeling of real sea floors with arbitrary shapes which provide an insight into the most important effects of the more common simplified shapes on the transmission loss of sound.