Central Section Research Articles

Comparison of Adult Female and Male PMHS Pelvis and Lumbar Response to Underbody Blast.

The goal of this study was to gather and compare kinematic response and injury data on both female and male whole-body Post-mortem Human Surrogates (PMHS) responses to Underbody Blast (UBB) loading. Midsized males (50th percentile, MM) have historically been most used in biomechanical testing and were the focus of the Warrior Injury Assessment Manikin (WIAMan) program, thus this population subgroup was selected to be the baseline for female comparison. Both small female (5th percentile, SF) and large female (75th percentile, LF) PMHS were included in the test series to attempt to discern whether differences between male and female responses were predominantly driven by sex or size. Eleven tests, using 20 whole-body PMHS, were conducted by the research team. Preparation of the rig and execution of the tests took place at the Aberdeen Proving Grounds (APG) in Aberdeen, MD. Two PMHS were used in each test. The Accelerative Loading Fixture (ALF) version 2, located at APG's Bear Point range was used for all male and female whole-body tests in this series. The ALF was an outdoor test rig that was driven by a buried explosive charge, to accelerate a platform holding two symmetrically mounted seats. The platform was designed as a large, rigid frame with a deformable center section that could be tuned to simulate the floor deformation of a vehicle during a UBB event. PMHS were restrained with a 5-point harness, common in military vehicle seats. Six-degree-of-freedom motion blocks were fixed to L3, the sacrum, and the left and right iliac wings. A three-degree-of freedom block was fixed to T12. Strain gages were placed on L4 and multiple locations on the pelvis. Accelerometers on the floor and seat of the ALF provided input data for each PMHS' feet and pelvis. Time histories and mean peak responses in z-axis acceleration were similar among the three PMHS groups in this body region. Injury outcomes were different and seemed to be influenced by both sex and size contributions. Small females incurred pelvis injuries in absence of lumbar injures. Midsized males had lumbar vertebral body fractures without pelvis injuries. And large females with injuries had both pelvis and lumbar VB fractures. This study provides evidence supporting the need for female biomechanical testing to generate female response and injury thresholds. Without the inclusion of female PMHS, the differences in the injury patterns between the small female and midsized male groups would not have been recognized. Standard scaling methods assume equivalent injury patterns between the experimental and scaled data. In this study, small female damage occurred in a different anatomical structure than for the midsized males. This is an important discovery for the development of anthropomorphic test devices, injury criteria, and injury mitigating technologies. The clear separation of small female damage results, in combination with seat speeds, suggest that the small female pelvis injury threshold in UBB events lies between 4 - 5 m/s seat speed. No inference can be made about the small female lumbar threshold, other than it is likely at higher speeds and/or over longer duration. Male lumbar spine damage occurred in both the higher- and lower lower-rate tests, indicating the injury threshold would be below the seat pulses tested in these experiments. Large females exhibited injury patterns that reflected both the small female and midsized male groups - with damaged PMHS having fractures in both pelvis and lumbar, and in both higher- and lower- rate tests. The difference in damage patterns between the sex and size groups should be considered in the development of injury mitigation strategies to protect across the full population.

Fingerprinting the geochemical signals of episodic arc activity in the Sierra Nevada batholith in space and time

Although subduction is a continuous process, arc system behavior is non-steady-state, leading to uncertainty surrounding the composite spatial and temporal evolution of transcrustal arc magma plumbing systems. This study integrates field, geochronologic, and geochemical data sets from the central Sierra Nevada arc section to investigate the extent to which spatial inheritance is recorded in arc geochemical compositions, and how these signals may be modified by dynamic arc behaviors through time, from arc-wide flare-ups, migration, and crustal thickening to regional magma focusing. Geochemical patterns across Mesozoic arc rocks characterize persistent spatial signals of inheritance, whereas geochemical trends during Cretaceous arc activity provide the temporal component of simultaneous dynamic processes. Distinct bulk-rock isotopic signals define each of the three Mesozoic magmatic flare-ups, which, during Cretaceous arc magmatism, is coupled with eastward arc migration. Additionally, Cretaceous magmatic and tectonic thickening doubled the thickness of arc crust, and magmatism was focused toward a central zone, culminating in the formation of the ∼1100 km2 Tuolumne Intrusive Complex. During magma focusing, temporal signals of magma mixing outweighed the previously pervasive signal of spatial inheritance. Distinct dynamic behaviors effectively primed the arc by the Late Cretaceous, generating transcrustal hot zones of increased magma mixing, recycling, long-term storage, and homogenization. Non-steady-state behavior in the Sierra Nevada resulted in mountain building and voluminous continental crust formation by transforming the physical, thermal, and chemical properties of the lithosphere over tens of millions of years.

Deformation Monitoring and Potential Risk Detection of In-Construction Dams Utilizing SBAS-InSAR Technology—A Case Study on the Datengxia Water Conservancy Hub

Deformation monitoring plays a pivotal role in assessing dam safety. Interferometric Synthetic Aperture Radar (InSAR) has the advantage of obtaining an extensive range of deformation, regardless of weather conditions. The Datengxia Water Conservancy Hub is the largest in-construction dam in China. To effectively assess the in-construction dam safety, the SBAS-InSAR (Small Baseline Subset-InSAR) technique and 86 Sentinel-1 images (from 11 February 2020, to 16 January 2023) have been employed in this study to monitor the deformation over the reservoir and its surrounding areas. The reliability of the SBAS-InSAR monitoring results over the study area was demonstrated by the in situ monitoring results. And the InSAR results show that the central section of the left dam exhibits the most substantial cumulative deformation, attributed to the maximal water pressure. This is closely followed by the left end of the dam, which reflects a similar but smaller deformation. However, the in-construction cofferdam facilities make the right-end section of the left dam more robust, and the deformation is the most stable. Additionally, significant deformation of the auxiliary dam slope has been identified. Moreover, the analysis indicated that the deformation of the four upstream slopes is closely related to the precipitation, which potentially poses a threat to the safety of the Datengxia Dam.

Artificial Nourishment Schemes along the Polish Coast and Lagoon Shores between 1980 and 2020, with a Particular Focus on the Hel Peninsula

This article reviews the literature covering the period from 1965 to 2020 dedicated to the issue of artificial beach nourishment along the Polish coast, with a particular focus on the Hel Peninsula. The primary sources used in this work include 34 reports from unpublished case studies and projects implemented by the Department of Maritime Hydrotechnics, Maritime Institute in Gdańsk, between 1971 and 2020. This paper also presents detailed information about the total fill volume in cubic meters of dredged material deposited along the Polish coast and lagoon shores in 1980–2020. During these 40 years, approximately 40.5 million m3 of sediment was deposited along the Polish coast and lagoon shores. Particular consideration was given to beach fills along the Hel Peninsula, which was at actual risk of breaking in its basal and central sections after intense storms at the turn of 1988 and 1989. The survey materials collected enabled the assessment of the coastal morphodynamics of the peninsula under the Coastal Protection Program through the prism of changes in the fill volume along the coastal sections, which were replenished with material coming from submarine deposits. The peninsula’s stability was also assessed, taking into account the ongoing climate change. Moreover, this article discusses the proposed rules and terms for protecting the Polish coast by way of artificial nourishment.

Potential improvement in combustion performance of a natural gas rotary engine mixed with hydrogen by novel bluff-body

Hydrogen/natural gas blends fuel is considered one of the ideal alternative fuels for improving the thermal efficiency and reducing carbon emissions of rotary engine. In order to further enhance the combustion and power performance of rotary engine, a new method of the setting of bluff bodies in the cylinder was proposed. The influence of bluff-body settings in the cylinder on the combustion, power performance, and NO generation was numerically studied under different ignition timings. The results indicated that in-cylinder bluff-body settings could influence flame propagation by affecting the turbulent kinetic energy and mixture distribution during the process from the late compression stroke to the combustion stroke. Further, for any fixed bluff-body shape in the cylinder, there is a trade-off relationship between the non-blockage ratio and squish velocity at the cylinder block center section as the ignition timing is progressively advanced or delayed. Consequently, considering the above trade-off relationship, the triangular slotted bluff-body in combination with an ignition timing of 30° CA (BTDC) could be used to achieve the maximum improvement in the combustion and power performance of rotary engine. The peak pressure exhibited a growth of 4.83%, and the indicated mean effective pressure increased by 1.46%.

Dynamics of currents in the Qiongzhou strait during spring and summer based on a numerical simulation

A high-precision three-dimensional hydrodynamic model based on the Semi-implicit Cross-scale Hydroscience Integrated System Model (SCHISM) was constructed to investigate the characteristics of residual currents in the Qiongzhou Strait during spring and summer. Results reveal an overall westward transport in the strait during spring and summer. However, the results also support the potential occurrence of transient eastward Eulerian residual currents, which should be evident predominantly at the surface in the central and eastern sections of the strait and mainly characterised by subtidal oscillations. The direction and intensity of these residual currents indicate a pronounced influence of pressure gradient forces on both sides of the strait. The eastward flow observed in spring may represent a compensatory mechanism resulting from the relaxation period of long-term easterly winds, whereas the generation of eastward residual currents in summer is influenced by wind stress curl differences in both the western and eastern areas of the strait. The direct impact of the summer monsoon on the flow field in the strait is relatively weak. Additionally, the direction and intensity of the residual currents in the strait exhibit potential interannual variations that are directly associated with interannual wind variations. This study provides valuable insights in relation to the ongoing discourse on the dynamics of residual currents in the Qiongzhou Strait.

Numerical Investigation of Hydrogen Combustion in a Chamber with Guide Ring and Double Jets

ABSTRACT To investigate the turbulent flow in a combustor with double jets and guide ring, the simulated cases include different guide ring angles of 95°, 105°, 115°, 125° and 135°. The distributions of velocity, turbulent kinetic energy (k), temperature, flame stretch rate ( κ ), combustion efficiency( η ), synergy angle( β ), and NO emissions are analyzed. Results show that the guide ring influences the combustion performance, and the degree of impact increases with increasing the guide ring angle (α). The 95° guide ring has a relatively minor effect. However, when α ≥ 105°, increasing α promotes the mixing between the double jets and enhances k, temperature uniformity, synergy effects, η and κ . During α from 95° to 135°, streamlines initially exhibit bending at the guide ring trailing edge, then inner recirculation zones (IRZ) appear. At the center section, average k/k 0 increases from 2.51 to 19.50, β decreases from 77.59° to 71.97°, and κ increases from 243.65 s−1 to 555.47 s−1. Compared to these without the guide ring, the values for the case with α = 135° are 8.82, 1.09 and 0.47 times, respectively.

Analyzing the Current State and Visibility of Diversity, Equity, and Inclusion Initiatives at Urology Residency Programs

ObjectiveTo analyze AUA urology residency program websites to determine visibility of DEI initiatives. There is growing interest in diversity, equity, and inclusion (DEI) initiatives by urology applicants, and in recent years, urology programs have invested in efforts to promote DEI. MethodsAll ACGME-accredited urology residency program with a website were assessed. Military programs were excluded. A DEI Score Card was developed using published pillars of DEI, including five domains: departmental inclusion, pipeline growth, departmental education, community engagement, and faculty demographics. Program Doximity rank, address, and surrounding demographics were collected to determine predictors of investing in DEI. Results141 urology residency websites were included for analysis. Only 40.7% of programs referenced DEI on their webpage, and 21.4% offered funded mentorship opportunities. Department education and community engagement were the least popular initiatives. The Western, Northeastern, and North Central sections had the highest DEI total score with wide variation across domains. Mention of DEI was not associated with program’s county-level social vulnerability or percent minority but was associated with being a top 50 program (OR=4.0; 95% CI 1.8, 8.9; p=0.0007). DiscussionLess than half of academic urology programs' websites referenced DEI initiatives. Using a DEI score card, our study shows that investment in diversity, equity, and inclusion varies widely by AUA section, and greater investment is positively correlated with program rank. Our DEI score card serves as a tool that programs can use to assess their current DEI investment, identify areas for improvement, and ensure existing initiatives are visible to applicants.

Research on the thermal performance and stability of three-dimensional array pulsating heat pipe for active/passive coupled thermal management application

The efficient heat transfer performance of three-dimensional pulsating heat pipes can effectively deal with the heat dissipation problems in the field of electronics integration. However, the large contact thermal resistance and complex layout limit the actual cooling efficiency. In this study, a novel three-dimensional array pulsating heat pipe (3D-APHP) with a dual-plane structure was designed. The top and bottom of the 3D-APHP are mounted with flat plates, and the center section is connected by multiple parallel array tubes. The planar and array structures enhance the flexibility in the actual layout of the pulsating heat pipe to accommodate space constraints. The effects of different conditions (working fluid, filling rate, heating power, tube diameter and installation condition) on the heat transfer performance and uniform temperature performance of 3D-APHP were investigated. It is found that 3D-APHP demonstrates efficient heat transfer capability and temperature uniformity. The minimum thermal resistance and maximum thermal conductivity can reach 0.059 °C/W and 170.1 KW/m °C, respectively. Moreover, 3D-APHP exhibits good heat transfer performance across different installation positions with a maximum thermal resistance not exceeding 1.1 °C/W, revealing significant potential for applications. Meanwhile, the two-phase heat transfer process inside the 3D-APHP was analyzed. The uniform vapor–liquid plug distribution can significantly strengthen the thermal performance of the 3D-APHP.

Using vulnerability assessment to characterize coastal protection benefits provided by estuarine habitats of a dynamic intracoastal waterway.

The existence of coastal ecosystems depends on their ability to gain sediment and keep pace with sea level rise. Similar to other coastal areas, Northeast Florida (United States) is experiencing rapid population growth, climate change, and shifting wetland communities. Rising seas and more severe storms, coupled with the intensification of human activities, can modify the biophysical environment, thereby increasing coastal exposure to storm-induced erosion and inundation. Using the Guana Tolomato Matanzas National Estuarine Research Reserve as a case study, we analyzed the distribution of coastal protection services-expressly, wave attenuation and sediment control-provided by estuarine habitats inside a dynamic Intracoastal waterway. We explored six coastal variables that contribute to coastal flooding and erosion-(a) relief, (b) geomorphology, (c) estuarine habitats, (d) wind exposure, (e) boat wake energy, and (f) storm surge potential-to assess physical exposure to coastal hazards. The highest levels of coastal exposure were found in the north and south sections of the Reserve (9% and 14%, respectively) compared to only 4% in the central, with exposure in the south driven by low wetland elevation, high surge potential, and shorelines composed of less stable sandy and muddy substrate. The most vulnerable areas of the central Reserve and main channel of the Intracoastal waterway were exposed to boat wakes from larger vessels frequently traveling at medium speeds (10-20 knots) and had shoreline segments oriented towards the prevailing winds (north-northeast). To guide management for the recently expanded Reserve into vulnerable areas near the City of Saint Augustine, we evaluated six sites of concern where the current distribution of estuarine habitats (mangroves, salt marshes, and oyster beds) likely play the greatest role in natural protection. Spatially explicit outputs also identified potential elevation maintenance strategies such as living shorelines, landform modification, and mangrove establishment for providing coastal risk-reduction and other ecosystem-service co-benefits. Salt marshes and mangroves in two sites of the central section (N-312 and S-312) were found to protect more than a one-quarter of their cross-shore length (27% and 73%, respectively) from transitioning to the highest exposure category. Proposed interventions for mangrove establishment and living shorelines could help maintain elevation in these sites of concern. This work sets the stage for additional research, education, and outreach about where mangroves, salt marshes, and oyster beds are most likely to reduce risk to wetland communities in the region.

Low-cycle fatigue behaviour of extruded 7075 aluminium alloy bar: Competition of grain sizes and textures

The low-cycle fatigue (LCF) behaviour of a large 7075 aluminium alloy bar was investigated, and the results indicated that the microstructure at the center (0R) and surface section of the bar (R) were different in terms of grain sizes and textures. The microstructure of the 0R specimen was characterised by coarser elongated grain and higher <111> texture intensity compared to that of the R specimen. The LCF life of the 0R specimen was higher than that of the R specimen at a strain amplitude range of 0.6%–0.9%, thereby indicating the dominant effect of higher texture intensity. However, the 0R specimen sustained short LCF life at low strain amplitudes of 0.4% and 0.5%, indicating the predominant effect of grain refinement. The fracture analysis results indicated that there were wider striations for the 0R specimen at a strain amplitude of 0.4%. Interestingly, the yield strength, ultimate tensile strength and elongation of the 0R specimen were higher than that of the R specimen. The higher mechanical properties of the 0R specimen was consistent with its longer low cycle fatigue life at strain amplitude range of 0.6%–0.9%. Moreover, the features of the fracture, including fracture initiation and fast fracture regions, were also elaborated. The competition of grain sizes and texture evolutions determined the LCF life of the alloy depending on the strain amplitude range: the grain size effect gradually overshadowed that of the texture with decreasing strain in terms of fatigue life.

Factorial analysis of road infrastructure related to traffic accidents occurred in Neiva in the years 2017-2018

The transportation sector has been fundamental in Colombia and faces serious consequences in terms of traffic accidents. This paper examines the relationship between accidentability and most outstanding road infrastructure factors in ten urban stretches of Neiva in the period 2017-2018, following the inclusion and exclusion criteria of the International Road Assessment Program (IRAP) for developing countries in order to characterize the state of road infrastructure of the selected points. The results showed that the central sections of the city tend to be related to the day, time, type of vehicle and victim, attribute and direction of the road. The motorcyclist was the road actor most vulnerable to injuries and fatalities, Saturday and 8:00 am was where more crashes occurred. The road infrastructure factors contributing to accidents highlight the relevance of the environment in the city.

The variation of the 400 mm isohyet and its influence mechanism on the Qinghai-Tibet Plateau from 1982 to 2021

The Qinghai-Tibet Plateau (QTP) has experienced an overall increase in humidity over recent decades, but the changes in aridity and humidity within the transitional climate zone, as well as the underlying factors driving these changes, remain unclear. We present a framework to quantify the spatiotemporal variations transitional zone indicated by 400 mm isohyets and its driving factors on the QTP. The results show that the 400 mm isohyets has moved an average of 87.85 km to the north-west direction, moving an average 0.04 km per year, and a maximum distance traveled of 261 km (northernmost orientation) during the past four decades. Over time, the variation in isohyets exhibited distinct piecewise characteristics and obvious spatial differences. The central section (95°E–101°E) remained relatively stable, whereas the eastern section (101°E–104°E) and western section (91°E–95°E) experienced violent fluctuations. The east–west boundary of the spatiotemporal movement of the 400 mm isohyets was utilized to delineate the eastern humid zone, transitional zone, and western arid zone. The transition zone interannual precipitation has experiences more significant interdecadal oscillations between dry and wet climates, while the western region has experienced the opposite. The East Asian summer monsoon (EASM) exhibited a positive correlation with precipitation, increased precipitation is the main factor driving the westward and northward movement of the 400 mm isohyets. The vegetation response to precipitation exhibited greater variability in the transitional zone. This study provides a novel reference for quantitatively comprehending the aridity and humidity of climatic conditions, as well as the driving mechanisms behind regional climate change in the QTP.

The effect of the viscoelastic support and GRPL-reinforced foam material on the thermomechanical vibration response of piezomagnetic sandwich nanosensor plates

This paper investigates the vibration characteristics of a sandwich nanosensor plate composed of piezoelectric materials, specifically barium and cobalt, in the upper and lower layers, and a core material consisting of either ceramic (silicon nitride) or metal (stainless steel) foams reinforced with graphene (GPRL). The study utilized the novel sinosoidal higher-order deformation theory and nonlocal strain gradient elasticity theory. The equations of motion for nanosensor sandwich graphene were derived using Hamilton's principle, considering the thermal, electroelastic, and magnetostrictive characteristics of the piezomagnetic surface plates. These equations were then solved using the Navier method. The core element of the sandwich nanosensor plate can be represented using three distinct foam variants: a uniform foam model, as well as two symmetric foam models. The investigation focused on analyzing the dimensionless fundamental natural frequencies of the sandwich nanosensor plate. This analysis considered the influence of three distinct foam types, the volumetric graphene ratio, temperature variation, nonlocal parameters, porosity ratio, electric and magnetic potential, as well as spring and shear viscoelastic support. Furthermore, an analysis was conducted on the impact of the metal and ceramic composition of the central section of the sandwich nanosensor plate on its dimensionless fundamental natural frequencies. In this context, the use of ceramic as the central material results in a mean enhancement of 33% in the fundamental natural frequencies. In contrast, the incorporation of graphene into the core material results in an average enhancement of 27%. The thermomechanical vibration behavior of the nanosensor plate reveals that the presence of graphene-supported foam and a viscoelastic support structure in the core layer leads to an increase in thermal resistance. This increase is dependent on factors such as the ratio of graphene, porosity ratio of the foam, and parameters of the viscoelastic support. Metal foam or ceramic foam has been found to enhance thermal resistance when compared to solid metal or ceramic core materials. The analysis results showed that it is important to take into account the temperature-dependent thermal properties of barium and cobalt, which are piezo-electromagnetic materials, and the core layer materials ceramics and metal, as well as the graphene used to strengthen the core. The research is anticipated to generate valuable findings regarding the advancement and utilization of nanosensors, transducers, and nano-electromechanical systems engineered for operation in high-temperature environments.

Microstructural Heterogeneity and Property Variations in Cast and Vacuum Hot-Pressed CoCrPtB Alloy.

Limited research has been undertaken regarding the homogeneity of CoCrPtB alloy billets. A CoCrPtB alloy was processed through casting and vacuum hot pressing. This investigation delved into the interconnection between the secondary dendrite arm spacing (SDAS) in the as-hot-pressed samples and their corresponding attributes, specifically Vickers hardness and magnetic properties. Systematic sampling was conducted on the cross-sectional layer and longitudinal surface. Upon examination of the cross-sectional layer proximate to the uppermost region of the hot casting, a discernible parabolic trend was observed for the SDAS that exhibited a gradual increment from the peripheral regions toward the central area along the width. Simultaneously, the fraction of the dendrite phase displayed a consistent linear decline, attaining its peak value at the central portion of the billet. Conversely, on the longitudinal surface, SDAS and the fraction of the dendrite phase remained fairly uniform within the same column sampling regions. However, a notable divergence was identified in the central section, characterized by an augmented SDAS and diminished dendrite phase content. This inherent microstructural inhomogeneity within the CoCrPtB alloy engendered discernible disparities in material properties.

Study on the steady-oscillatory transition of three-dimensional (3D) natural convection via Hopf bifurcation

The transition from steady-state flow to periodic oscillatory flow for the natural convection by Hopf bifurcation is investigated in a three-dimensional (3D) cavity. The spectral collocation method (SCM) in combination with the artificial compressibility method (ACM), which is developed by ourselves as a numerical method SCM-ACM with high accuracy, is employed to solve the governing equations directly instead of linear stability analysis method that is commonly used for the research on flow instability. The results show that the amplitude decays exponentially with time and the decay rate is linear with the Grashof number (Gr). The critical Grashof number for steady-oscillatory transition is obtained as Grcr = 3.423 × 106. The dimensionless angular frequency ωcr = 0.24 is also determined by Fourier analysis. In this work, we also examine the heat-momentum interactions within the boundary layers, visualize the periodic oscillations of temperature and velocity amplitudes, and analyze the origin of instability from multiple angles. The results show that large oscillations of velocity and temperature are observed near the isothermal walls. The oscillation is enhanced by the increase of thermal boundary layer thickness and flow velocity at both ends of isothermal walls. The maximum velocity and temperature amplitudes appear at the lower left and upper right corners of the mid-plane (Z = 0.5), where are the origin of instability, and the spanwise walls are almost independent of oscillations. The oscillatory flow of natural convection in three-dimensional cavity originates from the continuously increasing buoyancy force, and its transition occurs by Hopf bifurcation. Moreover, the temperature amplitude exhibits a wavy distribution on the mid-plane (X = 0.5) and strongly depends on the depth Z. These results provide benchmark data for future numerical studies and engineering application.

Determination of the Sound Absorption Area Inside an Elementary Classroom Using Three Acoustical Methods: Computer Modeling, 1/10-Scale Model Experiment, and Field Acoustic Measurement

Acoustic standards for classrooms around the world are still being studied, but the placement of sound-absorbing materials to meet these standards is still unclear. The present study examined an appropriate location for applying sound-absorbing materials inside an elementary classroom to ensure speech intelligibility while meeting the RT criterion using three scientific experimental methods, namely, computer modeling, a 1/10-scale model, and field acoustic measurement. A sound-absorbing material was applied to the rear wall or ceiling, and the ceiling was further divided into front, center, and rear sections. The acoustic performance was predicted using a 3D computer model of a standardized classroom based on the location of the sound-absorbing material. Subsequently, a 1/10-scale model following the law of similarity was used to compare the acoustic performances based on the location of the sound-absorbing material. Finally, field measurements were performed in an actual classroom to verify the acoustic performance based on the location of the sound-absorbing material. The findings revealed that the sound-absorbing material was most effective when applied to the rear wall, followed by application at the center, front, and rear of the ceiling.

A numerical investigation of the behavior of a tunnel with adaptive anti-dislocation measures subjected to the action of fault dislocation

In the context of long-distance cross-basin water transfer projects, the water conveyance tunnel serves as a pivotal component in mitigating regional disparities between economic development and water resources allocation. However, in high seismic-intensity areas of southwest China, geological complexities and densely distributed active faults present formidable challenges. Consequently, the construction of water conveyance tunnels necessitates traversing one or more active fault zones. This study examines the impact of an adaptive tunnel structure in the presence of fault dislocation, focusing on the Xianglushan Tunnel, a constituent of the Central Yunnan Water Diversion Project. Taking the Longpan-Qiaohou Fault F10-1 as a case study, we assess the influence of active faults on the anti-dislocation adaptive structure of the Xianglushan Tunnel, considering factors such as displacement, relative deformation, maximum principal stresses, and longitudinal equivalent internal force in critical tunnel sections. Numerical calculations validate the efficacy of this adaptive structure in reducing induced internal forces and deformations of the tunnel lining. The results show that, under the influence of strike-slip dominated fault movement, one side of the tunnel exhibits tensile stress, with a magnitude of approximately 5 MPa. The maximum normal and tangential deformation of the hinge joint is concentrated in the central section of the fault zone. The incorporation of an articulated adaptive design significantly enhances the stress state of lining under dislocation condition. These research results directly inform the engineering design and construction of water conveyance tunnels traversing active fault regions, providing valuable guidance for related tunnel construction endeavors.

Comparison of diagnostic values between 2D three-section ultrasound and 3D tomographic ultrasound imaging for fetal cleft palate at 11–13+6 weeks

ObjectiveTo assess diagnostic values of 2D three-section ultrasound including central sagittal section of the face, axial section of the superior alveolar process, and coronal section of the posterior triangle of the nose and 3D tomographic ultrasound imaging (TUI) in fetal cleft palate at 11–13+6 weeks. Methods21 cleft palate fetuses who were delivered or induced in our hospital from January 2018 to May 2021 were enrolled. All fetuses with cleft palate underwent nuchal translucency (NT) measurement and screening at 11–13+6 weeks. Relevant findings of cleft palate detected by 2D and 3D TUI during NT screening were retrospectively analyzed. The cleft palate detection rate was compared between two groups. ResultsThe detection rates of 3D TUI and 2D three-section ultrasound for cleft palate were 0.857 (18/21) and 0.810 (17/21), with no statistical significance (P > 0.05). The detection rates on triangular coronal section of the posterior nose were by 2-D three-section ultrasound was 81.0%, significantly higher than 52.3% (11/21) and 66.6% (14/21) on the central sagittal section and axial section of the superior alveolar process (both P < 0.05). ConclusionBoth 2D three-section ultrasound and 3D TUI yield high diagnostic value for cleft palate at 11–13+6 weeks. The detection rate of cleft palate on the coronal section of the posterior triangle of the nose by 2D three-section ultrasound is higher compared with those on the remaining two planes.

Using Spatial Modeling to Evaluate LED Light Intensity and Uniformity in Commercial Broiler Houses during Brooding and Tunnel Conditions

Highlights During brooding, more than 97% of the floor area of new broiler houses was above target light intensity, however, in aged houses less than 0.2% of the floor area was above the target. During tunnel conditions, less than 6% of the floor area met the target light intensity range (0.18–0.22 lx) for both aged and new houses. All floor areas in the fan section exceeded the target light intensity in both aged and new houses in all the farms due to light intrusion from the tunnel fans. Bulbs need to be periodically replaced to meet minimum target levels during brooding and light dimmer adjustments need to be made to meet light intensity targets during tunnel ventilation. Abstract. Commercial broiler companies set specific light intensities and photoperiods during different stages of live production to manage bird behavior and growth and to support health and welfare. However, it is currently unknown how much of the floor area in commercial houses is within the target levels set by companies. Therefore, a field survey of twenty 18.3 × 152.4 m broiler houses on five farms was performed to evaluate in-situ light intensity and uniformity in two house sections during brooding [evaporative pad section (pad) and the middle of the house section (mid)] and three sections during tunnel ventilation [pad, mid, and tunnel exhaust fan section (fan)]. Houses ranged in age from new (never used) to aged (5–8 years old). Light intensity measurements were recorded at 70 locations in each of the house sections (140 per house during brooding; 210 per house during tunnel). For tunnel mode, target light intensity values were categorized into above target (&amp;gt;0.22), within target (0.18–0.22 lx), and below target (&amp;lt;0.18 lx). For brooding mode, target light intensity values were below target (&amp;lt;43 lx) and within target (=43 lx). Geostatistics was used to map and calculate the percentage of floor area above, below, or within target thresholds. During brooding and tunnel conditions, the percent of floor area below target (&amp;lt;43 lx and &amp;lt;0.18 lx, respectively) was higher for aged houses than for new houses in the pad and midsections. All the floor area in the fan section was above target due to light intrusion from operating fans. During tunnel ventilation in the new houses, 4.5%, 6.0%, and 0.0% of the floor area at the pad, center, and fan sections, respectively, were within the 0.18 to 0.22 lx target threshold. However, in the aged houses, only 0.6%, 0.7%, and 0.0% of the floor area at the pad, center, and fan sections, respectively, were within the target range. This research illustrates that the newer houses did a better job at meeting or exceeding target light intensities and that very little of the floor area in new and aged houses during tunnel ventilation was within a 10% threshold of target intensities. Lack of light dimmer adjustment to account for lumen depreciation and accumulation of dust on the bulbs in the aged house most likely led to the lower overall light intensities. Because brood bulbs have a 100% lumen capacity and are not dimmed, a deep cleaning of the bulbs and periodic replacement are recommended if they are not reaching lighting targets. Periodic checking of light intensity is recommended, especially in older houses. Keywords: Broilers, House age, Light intensity, Spatial variation, Target.