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Purpose: The purpose of the study is to find the effect of convergent and divergent section length on the exit flow characteristics. Converging-diverging (CD) nozzle design can be difficult because of the necessity for precise geometry and an understanding of compressible fluid flow dynamics. To obtain the ideal supersonic speeds, it is challenging to make sure that the flow chokes at the throat, where the Mach number approaches one and then expands appropriately in the diverging region. The design needs to take into consideration things like the relationship between the area and Mach number, the impact of various pressure ratios and the flow's isentropic interactions. Design/methodology/approach: An ideal thrust production is achieved through the effective acceleration of exhaust gases through proper nozzle design. This paper numerically investigates impact of convergent, divergent length and nozzle pressure ratio on the exit Mach Number of CD nozzle supersonic jet. Exit Mach Number 1.6 convergent-divergent nozzle was used. In total, five cases were taken as the length of the both the convergent-divergent sections were modified with 50% of increment and decrement in its base length. At four different NPR, the analysis was carried out in over-expanded, correctly expanded and under-expanded conditions. The NPR used were 2, 3.2, 4 and 5. Findings: From the results, it is found that the convergent length linearly affects the exit Mach number, while the divergent length variation is not in order. Both the decreased and increased divergent length reduce the supersonic jet exit Mach number. The subsonic region is not majorly affected by the length. There is no rapid change in the flow properties whether the length is reduced or increased. Maximum of 2% to 3% variation is only noticed. On the contrary, a small change in supersonic region or divergent section makes major modification in the flow. Originality/value: To achieve the desired Mach number, not only the area of the nozzle but also the length affects it. In terms of divergent angle and area ratio, only most of the studies on nozzle have been focused. This study aims to find the impact of convergent length and divergent length on the exit Mach number. This could be used in a wide range of applications, including laser cutting, thermal spraying, gas turbines for power generation, rocket and jet engines, supersonic wind tunnels and turbo chargers in automotive engineering, because of their capacity to accelerate fluids to supersonic speeds. [ABSTRACT FROM AUTHOR]

Abstract The long-debated question in analytical chemistry of which of the area ratio or the intensity ratio is the more precise has yielded no definitive analytical conclusion. To address this issue theoretically, we derived analytical solutions for the lower limits of estimation precision for spectral parameters, including the intensity ratio and area ratio, based on the Cramér–Rao lower bound (CRLB) framework for a Gaussian spectrum. The precisions of spectral parameter estimations from the analytical solutions were consistent with results obtained from Monte Carlo simulations. Our theoretical and simulation results revealed that the precision of estimating the area ratio surpassed that of the intensity ratio by a factor of $$\sqrt{2}$$ 2 . Additionally, our experimental results aligned well with both theoretical predictions and simulation outcomes, further validating our approach. This increased precision of the area ratio is due to negative covariance between intensity and bandwidth, rather than the area containing more intensity information, as often misinterpreted. Consequently, and quite counter intuitively, prior bandwidth and intensity related information does not improve the area ratio precision: it worsens it. The analytical solution we derived represents the fundamental limits of spectral parameter measurement precision. Thus, it can be used as an alternative method for estimating the minimum error when experimental measurement uncertainty cannot be determined.

Copyright of Railway Construction Technology is the property of Railway Construction Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The long-debated question in analytical chemistry of which of the area ratio or the intensity ratio is the more precise has yielded no definitive analytical conclusion. To address this issue theoretically, we derived analytical solutions for the lower limits of estimation precision for spectral parameters, including the intensity ratio and area ratio, based on the Cramér–Rao lower bound (CRLB) framework for a Gaussian spectrum. The precisions of spectral parameter estimations from the analytical solutions were consistent with results obtained from Monte Carlo simulations. Our theoretical and simulation results revealed that the precision of estimating the area ratio surpassed that of the intensity ratio by a factor of 2 . Additionally, our experimental results aligned well with both theoretical predictions and simulation outcomes, further validating our approach. This increased precision of the area ratio is due to negative covariance between intensity and bandwidth, rather than the area containing more intensity information, as often misinterpreted. Consequently, and quite counter intuitively, prior bandwidth and intensity related information does not improve the area ratio precision: it worsens it. The analytical solution we derived represents the fundamental limits of spectral parameter measurement precision. Thus, it can be used as an alternative method for estimating the minimum error when experimental measurement uncertainty cannot be determined. [ABSTRACT FROM AUTHOR]

As the demand for high-density, high-performance technologies in semiconductor systems increases, efforts are being made to mitigate and optimize the issues of high current density and heat generation within interconnects to ensure reliability. While interconnects are the most fundamental pathways for transmitting current signals, there has been relatively little research conducted on them compared to individual unit devices from the perspective of overall system performance. However, as integration density increases, the amount of loss in interconnects also rises, necessitating research and development to minimize these losses. In this study, we propose a method to analyze power efficiency by utilizing the differences between simulation results and measured results of interconnect structures. We confirmed that the difference between theoretical resistance values and actual measured values varies with the contact area ratio between metal lines and vias, and we analyzed the power efficiency based on these differences. Using the findings, we proposed and validated a structure that can improve power efficiency. This study presents a method to analyze power efficiency and suggests ways to achieve higher power efficiency within the limited specifications of interconnects. This contributes to enhancing power efficiency and ensuring reliability, thereby preserving the performance of the overall system in highly integrated semiconductor systems. [ABSTRACT FROM AUTHOR]

The Chinese solar greenhouse (CSG) is a prevalent feature in agricultural practices within China. Nevertheless, the regulation of natural ventilation within this architectural structure remains suboptimal. Consequently, the development of a natural ventilation model becomes imperative for the effective management of the greenhouse environment. Of particular significance within these models is the consideration of the discharge coefficient as a pivotal parameter. Conducting a multi-case investigation into the variable-dependent discharge coefficient is crucial for both practical application and model advancement. This research delved into the impact of various factors, including the upper-lower vents area ratio (Aup/Alow), vent-greenhouse area ratio (Alow/Agreenhouse), lower vent position height (h/H), the incident angle of the external wind, and altitude, on the discharge coefficient (Cd) of CSG. A CFD model was developed for a scaled CSG with validation conducted through field experiments and wind tunnel tests. Results indicated a 61.6% reduction in Cd on average corresponding to an 80% decrease in Aup/Alow. Cd levels remained consistent following the attainment of an Aup/Alow ratio of 1.0. Besides, there was an average increase of 52.5% in Cd levels for every 0.09 decline in h/H, attributed to the blocking effect of the cover. Moreover, the ventilation rate and the pressure coefficient difference were utilized to construct a model of Cd pertaining to greenhouse design and ventilation operation, exhibiting a notable accuracy level of R2 = 0.95. Furthermore, the blocking effect of higher h/H was relieved as the incident angle θ decreased under the windward conditions. The increase in Aup/Alow and the decrease in Alow/Agreenhouse were identified as crucial factors contributing to the growth of Cd under leeward conditions. Ultimately, the high-altitude environment led to a rise in Cd levels in contrast to the low-altitude region. The increasing rate of Cd correlated positively with Alow/Agreenhouse and h/H initially, but exhibited a decline once Alow/Agreenhouse reached 0.036, remaining stable thereafter once h/H reached 0.18. In summary, a comprehensive examination of the discharge coefficient of CSG was undertaken, addressing a significant knowledge deficiency and laying the groundwork for advancements in the natural ventilation model and the intelligent control system for CSG. [ABSTRACT FROM AUTHOR]

Pain is the primary clinical indication of osteoarthritis (OA), and behavioral assessments in rodent pain models are widely used to understand pain patterns. These preclinical pain assessments can also help us to understand the effectiveness of emerging therapeutics for prolonged OA pain management. Along with evoked methods like mechanical allodynia and thermal hyperalgesia, non-evoked methods such as dynamic weight bearing (DWB) analysis are valuable tools for behavioral assessments of pain. Both these methods were utilized to study pain-induced behavioral changes in a monoiodoacetate (MIA)-induced osteoarthritic pain model, which is a well-established preclinical OA pain model. However, the utility of DWB analysis as an indicator of long-term pain sensitivity (more than 4 weeks) remains largely unexplored. Understanding the long-term sensitivity of DWB is valuable to study the effectiveness of novel prolonged pain-relieving therapeutics. Here, we studied the dynamic behavioral changes in MIA-induced OA rats over a period of 16 weeks using DWB measurements. Female Sprague Dawley rats were injected in the right knee joint with MIA (3 mg) using X-ray guidance. Multiple dynamic postural evaluations such as ipsilateral weight percentage, paw area, contralateral/ipsilateral weight ratio and area ratio were assessed to understand the behavioral changes. The data showed that the ipsilateral weight bearing percentage alone is not sufficient to assess pain-related behavior beyond 6 weeks. This study shows the advantages and limitations of dynamic weight bearing as an assessment tool for the long-term progression of pain behavior in MIA-induced OA rats. [ABSTRACT FROM AUTHOR]

Abrupt section changes are a classic problem in the study of flow in cylindrical ducts or pipes. For its analysis, there are a wide set of exiting data from previous studies, among which some authors stand out and will be mentioned. Those previous works have been used to obtain reliable results for the resolution of section changes along a pipe, either due to cross area increases or reductions on a 1D basis. It is also known that a numerical 2D axisymmetric simulation (CFD) could find a consistent result compared to experimental data in almost all fluid flow fields. The main novelty of the present study is the development of a simple numerical approach used to solve the minor loss calculation. Firstly, a theoretical analysis is developed, and then the results of the numerical simulations carried out on the behavior that affects the water and air flow rate in an abrupt section change, for both contraction and expansion problems, are presented. In both cases, the results are analyzed with different meshes (discretizations) and turbulence models. Finally, the obtained numerical results are compared with those in the technical literature. Also, a theoretical approach is shown in order to show a whole frame of the discussion. The core results are the loss coefficient evolution as a function of the section change both for the sudden contraction and the expansion of a pipe flow. As the results follow the existing experimental values, it is concluded that the developed model provides a feasible and quick design tool to analyze possible geometrical changes without the need for further experiments. [ABSTRACT FROM AUTHOR]

Biowall is one of the several innovative strategies people use to build a comfortable interior atmosphere with living plants. This research attempts to trace the gaps in the previous analysis as a 'state of the art' with a literature review method by focusing on the biowall method, area ratio and types of plants. Biowall performance is mainly related to the influence of thermal, visual, audial, and respiratory comfort. It is an essential topic used to induce atmospheric interiors, such as temperature, humidity, light intensity, sound insulation and absorption, CO2, HCHO, VOC, and particulate levels. The results showed that the empirical methods used were actual scale-up and down experiments, laboratories in test chambers, simulation with specific software, and case research on in-situ biowall. The comparison between the biowall and room size varied significantly due to the absence of a legal basis and reasons. Ferns and succulents were the most widely used species to induce atmospheric comfort. Therefore, it is necessary to conduct further research on biowall physical comfort based on multisensory simultaneously and determine its standard dimension and digital integration. Subsequent researchers must further discuss home-scale biowall acceleration and utilization of food-medicinal plants. [ABSTRACT FROM AUTHOR]

Diffusers are mechanical devices that recover static pressure at the expense of the kinetic energy of flowing fluid. The present study is intended about the different design of S-shaped diffusers and its performance characteristics using ANSYS FLUENT17.1 software. The characteristics have been achieved for design of turning angle 62.50/62.50for constant circular center line length 600 mm, constant inlet cross-sectional area 100 × 100 mm2 with constant aspect ratio 2.0 at the outlet for different design of area ratio i.e., 2, 4, and 6 respectively. Incompressible flow analysis has been made at Mach number 0.1176 at the entry of the duct using realizable k-ɛ, standard k-ɛ, and renormalized group k-ɛ model. It has been discovered that flow separation increases, flow uniformity at the exit decreases and overall static pressure loss coefficient (CP) value increases by increasing area ratio for all the design considered. It is also noticed that crossflow velocity is more prominent in the case of the renormalized group k-ɛ turbulent model. Finally, it is found that for the design of an area ratio 2 and 6 the present model gives the best performance in terms of stagnation pressure loss coefficient (CL) and static pressure loss coefficient (CP) respectively. [ABSTRACT FROM AUTHOR]

This study experimentally investigates the influence of dimple (DHS), flat plate (FHS), and trapezoidal heat spreader (THS) cooling systems on thermal regulation of low concentrated solar cell (LCPV). It is performed at 1.5 and 2 HS/PV area ratio and HS thicknesses 1 and 2 cm under 3100 W/m2 solar irradiance. Results reveal that using DHS outperforms other cooling systems in terms of cell temperature and electric performance. Increasing HS area ratio and thickness significantly enhances PV performance. DHS, PHS, and THS achieve maximum PV temperature reduction of 44.4, 43.2, and 41°C and PV efficiency improvement of 16.89%, 14.87%, and 13.9%, respectively. [ABSTRACT FROM AUTHOR]

The single floating stone column behavior in very soft soils with a low undrained shear strength of Cu ≤ 20 kN/m² was studied in the finite-element method to investigate the influence of stone column's area ratio on the normalized pressure-settlement curves of circular footings of different diameters. The studied cases consist of stone columns of 1.0 m in diameter Ds and lengths Ls of (4 m, 6 m, and 7.5 m). The diameter of footings Df is (1.0 m, 1.2 m, 1.4 m, 1.6 m, 2.0 m, 2.5 m, and 3.5 m) which covers the area ratios with a range of 100 to 8.16 %. A total of 28 runs were carried out using the Ansys program to simulate the case for improved and unimproved soil. In the axisymmetric numerical model, the connection between the stone column and the adjacent contact clay soil was modeled as bonded type. The results of the analysis showed that there is a clear relationship between the bearing ratio (q/cu improved) / (q/cu unimproved) and the normalized settlement (S/Df) of the composite structure and the area ratio Ar% of the stone columns. The deformation ratio (Streated/Suntreated) and the footing diameter are related using a straightforward equation. In comparison to footings with a low area ratio, the footing displays a lower value of settling when subjected to the same pressure. By decreasing the diameter of the footing, the normalized settlement decreases for the same normalized q/cu values. The bearing ratio depends on the stone column length ratio Ls/Ds and settlement ratio. It is from 2.2 at a 100% area ratio and 1.23 at a 16% area ratio. [ABSTRACT FROM AUTHOR]

Background and Aim: The microsurface structure reflects the degree of damage to the glands, which is related to the invasion depth of early gastric cancer. To evaluate the diagnostic value of quantitative microsurface structure analysis for estimating the invasion depth of early gastric cancer. Methods: White‐light imaging and narrow‐band imaging (NBI) endoscopy were used to visualize the lesions of the included patients. The area ratio and depth‐predicting score (DPS) of each patient were calculated; meanwhile, each lesion was examined by endoscopic ultrasonography (EUS). Results: Ninety‐three patients were included between 2016 and 2019. Microsurface structure is related to the histological differentiation and progression of early gastric cancer. The receiver operating characteristic curve showed that when an area ratio of 80.3% was used as a cut‐off value for distinguishing mucosal (M) and submucosal (SM) type 0–II gastric cancers, the sensitivity, specificity, and accuracy were 82.9%, 80.2%, and 91.6%, respectively. The accuracies for distinguishing M/SM differentiated and undifferentiated early gastric cancers were 87.4% and 84.8%, respectively. The accuracy of EUS for distinguishing M/SM early gastric cancer was 74.9%. DPS can only distinguish M‐SM1 (SM infiltration <500 μm)/SM (SM infiltration ≥500 μm) with an accuracy of 83.8%. The accuracy of using area ratio for distinguishing 0–II early gastric cancers was better than those of using DPS and EUS (P < 0.05). Conclusion: Quantitative analysis of microsurface structure can be performed to assess M/SM type 0–II gastric cancer and is expected to be effective for judging the invasion depth of gastric cancer. [ABSTRACT FROM AUTHOR]

As the demand for high-density, high-performance technologies in semiconductor systems increases, efforts are being made to mitigate and optimize the issues of high current density and heat generation within interconnects to ensure reliability. While interconnects are the most fundamental pathways for transmitting current signals, there has been relatively little research conducted on them compared to individual unit devices from the perspective of overall system performance. However, as integration density increases, the amount of loss in interconnects also rises, necessitating research and development to minimize these losses. In this study, we propose a method to analyze power efficiency by utilizing the differences between simulation results and measured results of interconnect structures. We confirmed that the difference between theoretical resistance values and actual measured values varies with the contact area ratio between metal lines and vias, and we analyzed the power efficiency based on these differences. Using the findings, we proposed and validated a structure that can improve power efficiency. This study presents a method to analyze power efficiency and suggests ways to achieve higher power efficiency within the limited specifications of interconnects. This contributes to enhancing power efficiency and ensuring reliability, thereby preserving the performance of the overall system in highly integrated semiconductor systems.

Abstract Background and Aim The microsurface structure reflects the degree of damage to the glands, which is related to the invasion depth of early gastric cancer. To evaluate the diagnostic value of quantitative microsurface structure analysis for estimating the invasion depth of early gastric cancer. Methods White‐light imaging and narrow‐band imaging (NBI) endoscopy were used to visualize the lesions of the included patients. The area ratio and depth‐predicting score (DPS) of each patient were calculated; meanwhile, each lesion was examined by endoscopic ultrasonography (EUS). Results Ninety‐three patients were included between 2016 and 2019. Microsurface structure is related to the histological differentiation and progression of early gastric cancer. The receiver operating characteristic curve showed that when an area ratio of 80.3% was used as a cut‐off value for distinguishing mucosal (M) and submucosal (SM) type 0–II gastric cancers, the sensitivity, specificity, and accuracy were 82.9%, 80.2%, and 91.6%, respectively. The accuracies for distinguishing M/SM differentiated and undifferentiated early gastric cancers were 87.4% and 84.8%, respectively. The accuracy of EUS for distinguishing M/SM early gastric cancer was 74.9%. DPS can only distinguish M‐SM1 (SM infiltration

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abrupt section changes are a classic problem in the study of flow in cylindrical ducts or pipes. For its analysis, there are a wide set of exiting data from previous studies, among which some authors stand out and will be mentioned. Those previous works have been used to obtain reliable results for the resolution of section changes along a pipe, either due to cross area increases or reductions on a 1D basis. It is also known that a numerical 2D axisymmetric simulation (CFD) could find a consistent result compared to experimental data in almost all fluid flow fields. The main novelty of the present study is the development of a simple numerical approach used to solve the minor loss calculation. Firstly, a theoretical analysis is developed, and then the results of the numerical simulations carried out on the behavior that affects the water and air flow rate in an abrupt section change, for both contraction and expansion problems, are presented. In both cases, the results are analyzed with different meshes (discretizations) and turbulence models. Finally, the obtained numerical results are compared with those in the technical literature. Also, a theoretical approach is shown in order to show a whole frame of the discussion. The core results are the loss coefficient evolution as a function of the section change both for the sudden contraction and the expansion of a pipe flow. As the results follow the existing experimental values, it is concluded that the developed model provides a feasible and quick design tool to analyze possible geometrical changes without the need for further experiments.

This research was conducted in the context of the semiconductor market, with a demand for high-performance and highly integrated semiconductor systems that simultaneously enhance performance and reduce chip size. Scaling down the metal line and via in back-end-of-line (BEOL) structures is essential to efficiently deliver power to scaling down devices. This study utilized the finite element method (FEM) simulation technique to model the heat and current distribution for enhancing the efficiency of scaled-down structures. Due to current flow bottlenecks, an increase in the area ratio of the via to metal line (as the via becomes relatively smaller) leads to a temperature rise due to Joule heating. This trend follows a second-degree polynomial form, and the point where the temperature doubles compared to when the area ratio is one is situated at an area ratio of three. The temperature increase caused by Joule heating ultimately leads to destruction of the via, which directly affects the reliability of the BEOL structure. These experimental results can provide guidelines for designing with reliability considerations in mind, particularly in today's semiconductor systems where significant scaling down is required in interconnect structures. They can also be widely applied to research aimed at developing interconnect structures that enhance reliability. [ABSTRACT FROM AUTHOR]

Abstract Background Previous physics-based analyses of arterial morphology in relation to pulsatile pressure and flow, with pulse wave reflection, focused on the large arteries and required assumptions about the relative thicknesses of arterial walls and the velocities of pulse waves in the arteries. A primary objective of this study was to analyze arterial morphology and pulse wave reflection, using physics-based wave propagation, which explicitly includes arterial stiffness, with potential autonomic flow regulation, for both large and small arteries. Methods Pulse wave reflections that occur at arterial bifurcations, and their impact on macrocirculation and microcirculation pulse pressures and flows, are analyzed using the physics of wave propagation and impedance matching. Results The optimum combinations of arterial dimensions and stiffnesses which minimize pulsatile reflections at arterial bifurcations are identified for both macrocirculation and microcirculation. The optimum ratio of arterial bifurcations’ branch-to-trunk luminal areas is predicted to have a value of 1.26, (with corresponding optimum stiffnesses) based on the principle that autonomic flow regulation minimizes pulsatile reflections. This newly predicted value of area ratio compares favorably with the Murray Scaling Law value of 1.26. For an area ratio of 1.26, the optimum bifurcation stiffness ratio is predicted to have a value of 1.12 for bifurcations in the macrocirculation and a value of 0.89 in the microcirculation. The analysis predicts that minimal pulsatile reflections may occur for area ratios not equal to 1.26, when vasodilation adjusts arterial stiffness to compensate for non-optimal arterial area ratios. The analysis predicts that the capillaries have about one-tenth the stiffness of the aorta, and the capillary bed possesses about one thousand times more total luminal area than the aorta. The analysis predicts there are about thirty generations, aorta to capillaries, of arterial bifurcations in an arterial tree. Conclusions The optimum arterial morphologies predicted by this physics-based analysis correspond to those observed in human vascular physiology. The contributions that arterial stiffnesses and dimensions make to optimal pulsatile flow are relevant to the development of pharmaceuticals related to autonomic vasodilation, to the development of optimally designed stents and to surgical procedures related to vascular modification.

The shear mechanical properties of structural plane are mainly determined by the surface roughness, and the roughness coefficient is the main method to characterize the roughness. At present, the research on the roughness coefficient is limited to a single dimension. Multi-angle and quantitative calculation of the roughness coefficient of structural plane can avoid the limitation of inaccurate calculation caused by single dimension analysis. Cubic granite blocks with structural plane are prepared by Brazilian splitting. High-precision 3D scanner is used to scan the prepared structural interview samples and obtain the point cloud data of the structural planes. At the same time, three-dimensional reconstruction of point cloud data is carried out by reverse software. The distribution frequency in the Z direction of the point cloud data, the relationship between the section ratio and joint roughness coefficient (JRC) values of the section line, and the relationship between the structural plane area ratio and the mean JRC values are studied. The results show that the distribution frequency in the Z direction of point cloud data can be used as a preliminary method to evaluate the roughness of structural surface. The relationships between section ratio and JRC value as well as area ratio of structural plane and mean JRC are both quadratic function. By numerical analysis, the binary function relation between the mean JRC of the structural planes and the section ratio and area ratio is established, and the empirical formula of the mean JRC of the structural plane is obtained. This study provides a "point-line-plane" idea to evaluate the roughness of discontinuities. The obtained empirical formula provides a new method for calculating the mean value of JRC of the structural plane.

A three dimensional computational fluid dynamic (CFD) analysis was conducted to understand the hydrodynamic performance of a dimple texture produced using recently invented low-cost dynamic-assisted tooling (DAT) in the machining process. Five different area ratios, αr of 0%, 1.63%, 3.26%, 6.53%, and 9.80%, and three different sliding speeds represented by Reynolds number, Re of 10, 45, and 80 were analyzed. From the study, there existed an optimum area ratio of 3.26%, which generated up to 290% higher load-carrying capacity compared to a fully textured surface. These findings revealed the benefits of dimple texture produced using DAT, as well as proposing the optimum area ratio needed to be considered in order to optimize the dimple performance for actual application on piston engine surfaces in the near future. [ABSTRACT FROM AUTHOR]

In this research article, a concept for a secondary RAdio Direction And Ranging (RADAR) angle of arrival based system with cooperative targets transmitting at 2.4 GHz and using Multiple Signal Classification (MuSiC) to determine the angles of incidence is investigated. In addition to introducing common algorithms and presenting thorough derivations, the system is first examined through simulations. To prove the concept, hardware, firmware, and software are developed. For MuSiC, we propose three novel methods to obtain the correct incident angle from the spectrum, especially in strong multipath environments. These methods work either for a single spectrum or for a combination recorded at multiple times. Together with the estimated angles of incidence, our methods determine measures on the respective likelihoods. Based on this, we additionally propose two algorithms for computing the final position. Our system is characterized in both a simple 20 m × 15 m outdoor and a 17 m × 13 m multipath indoor environment, where we achieve a mean angular error of 3◦ and a mean positioning error of 0.67 m for the former using only four base stations with four antennas each. Our novel approach shows position accuracy improvements of 15% outdoors and 25% indoors compared to classical MuSiC estimation. [ABSTRACT FROM AUTHOR]

The mechanism of interlayer bonding and its relationship with interface morphology in asphalt pavement is not well understood yet. This study aims at investigating the effect of interface morphology on the interlayer bonding performance of double-layered asphalt systems. Four double-layered asphalt systems were prepared with rubberized asphalt concrete (RAC), asphalt concrete (AC), and stone mastic asphalt (SMA) mixtures. To test the influence of different interlayer treatments, three conditions were studied: styrene-butadiene-styrene (SBS)-modified asphalt gravel seal (GS) coat (SBS-GS), rubber-modified asphalt gravel seal coat (RA-GS), and fiber-reinforced rubber–modified asphalt gravel seal coat (FR-GS). The influence of surface type and interface treatment on interface morphology and bonding properties were compared and analyzed using a series of indoor interlayer shear bonding tests under three temperature conditions in two phases. In addition, based on the three-dimensional (3D) scanning and reconstruction technique, the morphology of the nondestructively separated interface of double-layered systems with no interlayer treatment was obtained, and the mechanism of the influence of the interface morphology on the interlayer shear strength was analyzed in depth. The results showed that double-layered systems exhibited different macrotexture and roughness characteristics at interlayer surfaces, creating distinct interface morphology properties for each system type. Consequently, the interlayer bonding strength and performance of double-layered asphalt systems were affected accordingly. In this respect, the order of the interlayer shear strength of double-layered systems with different interlayer treatments at different temperatures ranked as RAC-13/RAC-20 > SMA-13/RAC-20 > SMA-13/AC-20 > AC-13/AC-20. It was demonstrated that the proposed interface area ratio (K) can be used for the characterization of the interface morphology and reflect the interlayer bonding state. Moreover, it was found that the interlayer treatment could influence the interface morphology to a certain extent and change the effective bonding between layers. As a result, the order of interlayer shear strength of different interlayer bonding treatments ranked as FR-GS> RA-GS > SBS-GS. Finally, aggregate gradation of the mixtures could also affect the morphological characteristics of the interface. [ABSTRACT FROM AUTHOR]

Background: Previous physics-based analyses of arterial morphology in relation to pulsatile pressure and flow, with pulse wave reflection, focused on the large arteries and required assumptions about the relative thicknesses of arterial walls and the velocities of pulse waves in the arteries. A primary objective of this study was to analyze arterial morphology and pulse wave reflection, using physics-based wave propagation, which explicitly includes arterial stiffness, with potential autonomic flow regulation, for both large and small arteries. Methods: Pulse wave reflections that occur at arterial bifurcations, and their impact on macrocirculation and microcirculation pulse pressures and flows, are analyzed using the physics of wave propagation and impedance matching. Results: The optimum combinations of arterial dimensions and stiffnesses which minimize pulsatile reflections at arterial bifurcations are identified for both macrocirculation and microcirculation. The optimum ratio of arterial bifurcations' branch-to-trunk luminal areas is predicted to have a value of 1.26, (with corresponding optimum stiffnesses) based on the principle that autonomic flow regulation minimizes pulsatile reflections. This newly predicted value of area ratio compares favorably with the Murray Scaling Law value of 1.26. For an area ratio of 1.26, the optimum bifurcation stiffness ratio is predicted to have a value of 1.12 for bifurcations in the macrocirculation and a value of 0.89 in the microcirculation. The analysis predicts that minimal pulsatile reflections may occur for area ratios not equal to 1.26, when vasodilation adjusts arterial stiffness to compensate for non-optimal arterial area ratios. The analysis predicts that the capillaries have about one-tenth the stiffness of the aorta, and the capillary bed possesses about one thousand times more total luminal area than the aorta. The analysis predicts there are about thirty generations, aorta to capillaries, of arterial bifurcations in an arterial tree. Conclusions: The optimum arterial morphologies predicted by this physics-based analysis correspond to those observed in human vascular physiology. The contributions that arterial stiffnesses and dimensions make to optimal pulsatile flow are relevant to the development of pharmaceuticals related to autonomic vasodilation, to the development of optimally designed stents and to surgical procedures related to vascular modification. [ABSTRACT FROM AUTHOR]

The development of the Ranque-Hilsch vortex tube has stagnated since the 1950s, when Hilsch improved the vortex tube proposed by Ranque. Consequently, the performance of vortex tubes has remained constant for the past 70 years. In addition to the unclear flow structure and energy separation mechanism of vortex tubes, the lack of a mature design method for vortex tubes has also limited its widespread adoption for industrial applications. The inlet nozzle and main tube parameters have been studied extensively, and matching the inlet with the main tube is considered an important step in the design of a vortex tube; however, this process has not been studied extensively. In addition, although the temperature drop at the cold exit is a commonly adopted performance benchmark, it is not possible to establish a close relationship between this parameter and the geometric parameters of a vortex tube. This study investigates the relationship between the cooling performance and the area ratio of a vortex tube. The results indicate that the inlet mass flowrate per unit area has a positive correlation with the cooling performance, and its influence on the performance of a vortex tube is higher than that of the distribution of the reverse flow boundary. Therefore, the inlet mass flowrate per unit area can potentially be a geometric performance benchmark. However, further studies are required to develop better guidelines for optimizing the design and to obtain a deeper understanding of the energy separation mechanism of vortex tubes. [ABSTRACT FROM AUTHOR]

Expansive clay soil has high potential of swelling due to minerals content which bind water, therefore, soil improvement is required to stabilize the swelling behavior by add binder additive such as lime in deep soil mixing method (DSM). In this study, Finite Element model approach was performed with embankment provided on the top of expansive clay layer to provide bearing layer for road construction. As the deep soil mixing is applied on the subgrade (expansive clay layer), some model variation is performed such as diameter variation with 0.4m; 0.6m; 0.8m, depth variation with 5m; 6.5m; 8m and space variation 0.8 m;1.2m;1.6m; 2.4m. Area ratio parameter also used for ease understanding of deep soil mixing behavior with so many model variations provided. Analysis results shows that higher area ratio of deep soil mixing will provide lower displacement value either immediate displacement or consolidation displacement. Moreover, plot result of area ratio shows that area ratio of 0.4 provide effective value regarding consolidation displacement and duration.

• An ejector that can be adjusted without disassembly was designed. • Saturated/undersaturated regions of the ejector were found during the tuning process. • The concept of operating condition coefficient-Γ is proposed. • The control scheme for variable operating conditions of the ejector was provided. • Effects of AR and NXP on the vortices of the premixing chamber were analyzed. The ejector has a substantial impact on the performance of the solar-driven ejector refrigeration system. This work designs an adjustable ejector without disassembly and performs numerical modeling of the geometric model to enhance the ejector capacity to adapt to various operating conditions; the simulations dependability was also validated using experimental evidence. The findings indicate that within the given operating conditions, the adjustable ejector efficiency increased by an average of 82.4 %; the COP of the system increased by an average of 72.8 %. It is also found that the adjustable ejector has a saturation region, where the ejector performance rapidly declines as the nozzle exit position increases. Under the given operating conditions, the functional relationship between the optimal area ratio and nozzle exit position is obtained. By defining the operating condition coefficient (Γ), the function of the Γ and optimal area ratio is obtained, which provides the adjustable ejector control logic. From the energy perspective, the influence of structural changes on the vortex near the premixing chamber wall is analyzed, and the basic internal reasons for how structural alterations affect the ejector performance are initially revealed. [ABSTRACT FROM AUTHOR]

This study elucidates the hydrothermal characteristics of a capillary-driven stepped heat pipe (SHP). An axisymmetric numerical simulation is performed to analyze the effects of step pattern, area ratio (AR), evaporator length (LE), and wick parameters on the system characteristics. The results of the numerical model show good agreement with data from literature. These results suggest that superior performance can be achieved with a two-sided step and a step with sudden contraction with an enlarged evaporator. SHPs with a large area ratio (AR > 1) and a long evaporator yield superior thermal and capillary performances; those with a small condenser diameter (AR < 1) are more likely to experience dryout. Wick parameters, such as porosity (ε) and wick type, play a vital role in the system performance. Numerical results under the studied conditions can provide a clear engineering guide for the design of SHPs used in various engineering applications. [ABSTRACT FROM AUTHOR]

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Background: The aim of this study was to assess the diagnostic role of acoustic radiation force impulse imaging (ARFI) in differentiating benign and malignant cervical nodes. Methods: This was a diagnostic accuracy cross-sectional study. All patients who underwent ultrasound-guided fine-needle aspiration cytology (FNAC) of cervical nodes were included. Patients without FNAC/biopsy and patients in whom cervical nodes were cystic or completely necrotic were excluded. FNAC was used as reference investigation to predict the diagnostic accuracy. In all cases, FNAC was carried out after the B-mode, color Doppler and the ARFI imaging. In patients with multiple cervical lymph nodes, the most suspicious node based on grayscale findings was chosen for ARFI. ARFI included Virtual Touch imaging (VTI), area ratio (AR), and shear wave velocity (SWV) for each node, and the results were compared with FNAC/biopsy. Results: The final analysis included 166 patients. Dark VTI elastograms had sensitivity and specificity of 86.2% and 72.1%, respectively, in identifying malignant nodes. Sensitivity and specificity of AR were 71.3% and 82.3%, respectively, for a cutoff of 1.155. Median SWV of benign and malignant nodes was 1.9 [95% confidence interval (CI), 1.56–2.55] m/s and 6.7 (95% CI, 2.87–9.10) m/s, respectively. SWV >2.68 m/s helped in identifying malignant nodes with 81% specificity, 81.6% sensitivity, and 81.3% accuracy. ARFI was found to be inaccurate in tuberculous and lymphomatous nodes. Conclusion: Malignant nodes had significantly darker elastograms, higher AR and SWV compared to benign nodes, and SWV was the most accurate parameter. ARFI accurately identifies malignant nodes, hence could potentially avoid unwarranted biopsy.

Abstract Objectives To evaluate the changes of Hounsfield units (HU) value in different types of Modic changes (MCs) and to analyze the correlation between the change of HU value and area ratio of MCs region, bone mineral density (BMD), and degree of intervertebral disc degeneration. Methods One hundred fifty-eight endplates with MCs were included and analyzed. HU values of MCs regions and adjacent vertebral corresponding regions without MCs were measured. The area ratio of MCs region was defined as the area of MCs divided by the area of endplate or the vertebral sagittal plane. BMD was measured by Dual-energy x-ray absorptiometry (DXA). Degree of intervertebral disc degeneration was evaluated based on Pfirrmann classification. According to the types of variables, descriptive statistics, Kolmogorove-Smirnov test, paired t-test, Wilcoxon signed-rank test, Independent-Samples T Test, and Pearson correlation analysis were used. Results The HU values in any types of MCs are significantly higher than that of adjacent vertebral corresponding regions without MCs (P

To study the influence of consolidation on the bearing capacity of the composite foundation in the process of caisson heightening, the consolidation characteristics of the sand pile composite foundation in the process of caisson heightening are discussed based on the sand pile composite foundation engineering of a large-scale onshore caisson foundation. The influence of loading duration and replacement rate of the sand pile are analyzed. Based on the area ratio method of pile-soil and the pile-soil stress ratio method, the formula of the ultimate bearing capacity of the sand pile composite foundation considering the consolidation effect is derived, which is compared with the measured value of the ultimate bearing capacity of the foundation. The results show that the time history curves of the bearing capacity of the composite foundation based on the two methods are close, and the initial bearing capacity is less than the measured value of bearing capacity, while the bearing capacity after consolidation is 68% and 80% higher than the natural strength of the composite foundation. This method considers the influence of consolidation on the bearing capacity of the foundation in the process of caisson heightening. It can avoid the problem of stagnant sinking of open caisson as it underestimates the actual bearing capacity of the foundation, and provides suggestions for calculation of ultimate bearing capacity of the composite foundation considering the influence of consolidation and formulating the reasonable construction scheme of open caisson.

Aiming at the method of using energy storage hydraulic cylinders to coordinate the lifting of the heavy manipulators to realize the gravitational potential energy recovery and utilization, the impacts of the different area ratios of the rodless cavity for the energy storage cylinders and the driving cylinders on the energy saving effectiveness of the systems were studied. The working principles of the energy storage cylinder cooperative driving circuits were analyzed to control the boom up and down, and the mathematical system model was established. Taking a 76 t hydraulic excavator as an example, a multi-disciplinary co-simulation model of the whole machine was constructed in Simulation X, and the accuracy of the model was verified by tests. According to this model, the system energy consumption characteristics of hydraulic excavators were optimized and simulated for the area ratio of the rodless cavity for the energy storage cylinders and the driving cylinders under no-load and loaded conditions. The simulation results show that: in the same working cycle, the output energy of the hydraulic pump of the optimized energy storage cylinder cooperative drive system is about 732.0 kJ, which saves bout 253.8 kJ compared with the energy before improvement, and the energy saving rate is increased from 27.2% to 46%, realizing the improvement of energy-saving effectiveness. [ABSTRACT FROM AUTHOR]

A new design method for ultrabroadband radar cross section (RCS) reduction by exploiting characteristic complementary polarization conversion metasurfaces (PCMs) is proposed and validated. The proposed method lifts the conventional bandwidth limitation enforced by the performance of a single PCM and expands the RCS reduction bandwidth. A systematic strategy for ultrabroadband RCS reduction design is developed and an effective reflection coefficient amplitude of the composite surface ($\Gamma _{ {eff}}$) is derived as a new RCS reduction indicator. Based on this indicator, complete polarization conversion (CPC) frequency points of PCM are identified as important characteristics, and PCM pairs with interleaved CPC points, termed as initial PCM (I-PCM) and complementary PCM (C-PCM), are designed to compensate each other for ultrabroadband RCS reduction. A scaling-and-tuning two-step method for designing the C-PCM of a specific I-PCM is developed and validated. To further improve RCS reduction performance, taking the ${\Gamma _{ {eff}}}$ as an indicator, the particle swarm optimization (PSO) algorithm is used to select the optimal I-PCMs, C-PCMs, and their area ratios. Finally, an ultrabroadband RCS reduction surface is designed, fabricated, measured, and validated. It realizes 10-dB monostatic RCS reduction ranging from 7.6 to 26.2 GHz (110.7% relative bandwidth) which exceeds the polarization conversion bandwidth of each individual PCM. Besides, good polarization insensitivity and bistatic RCS reduction performance are also obtained. The proposed method provides a new route for designing broadband RCS reduction surface based on PCMs with unsatisfactory characteristics and greatly alleviates the performance requirement for PCMs. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to assess the diagnostic role of acoustic radiation force impulse imaging (ARFI) in differentiating benign and malignant cervical nodes. Methods: This was a diagnostic accuracy cross-sectional study. All patients who underwent ultrasound-guided fine-needle aspiration cytology (FNAC) of cervical nodes were included. Patients without FNAC/biopsy and patients in whom cervical nodes were cystic or completely necrotic were excluded. FNAC was used as reference investigation to predict the diagnostic accuracy. In all cases, FNAC was carried out after the B-mode, color Doppler and the ARFI imaging. In patients with multiple cervical lymph nodes, the most suspicious node based on grayscale findings was chosen for ARFI. ARFI included Virtual Touch imaging (VTI), area ratio (AR), and shear wave velocity (SWV) for each node, and the results were compared with FNAC/biopsy. Results: The final analysis included 166 patients. Dark VTI elastograms had sensitivity and specificity of 86.2% and 72.1%, respectively, in identifying malignant nodes. Sensitivity and specificity of AR were 71.3% and 82.3%, respectively, for a cutoff of 1.155. Median SWV of benign and malignant nodes was 1.9 [95% confidence interval (CI), 1.56–2.55] m/s and 6.7 (95% CI, 2.87–9.10) m/s, respectively. SWV >2.68 m/s helped in identifying malignant nodes with 81% specificity, 81.6% sensitivity, and 81.3% accuracy. ARFI was found to be inaccurate in tuberculous and lymphomatous nodes. Conclusion: Malignant nodes had significantly darker elastograms, higher AR and SWV compared to benign nodes, and SWV was the most accurate parameter. ARFI accurately identifies malignant nodes, hence could potentially avoid unwarranted biopsy. [ABSTRACT FROM AUTHOR]

An active-vision process is presented by the affine invariability of the ratio of triangle areas to reconstruct the 3D object. Firstly, a plate with the triangle array is designed in the same plane of the planar laser. The image of the plate is rectified from the projection space to the affine space by the image of the line at infinity. Then the laser point and the centroids of the triangles constitute a new triangle that bridges the affine space and the original Euclidean space. The object coordinates are solved by the invariant of the triangle area ratio before and after the affine transformation. Finally, the reconstruction accuracy under various measurement conditions is verified by experiments. The influence analyses of the number of line pairs and the accuracy of the extracted point pixels are provided in the experimental results. The average reconstruction errors are 1.54, 1.79, 1.90, and 2.46 mm for the test distance of 550, 600, 650, and 700 mm, which demonstrates the application potential of the approach in the 3D measurement.

The goal of this study is to determine the role of the area ratio (AR) and the Reynolds number on the distribution of flow and pressure in the dividing manifold. For this purpose, five different models have been used to be analyzed under the test conditions. The first physical model is of 101.6 mm (4 in) in diameter for the master manifold in a regular longitudinal section and five sidelong of 50.8 (2 in) in diameter with a spacing of 220 mm. This model has been utilized to determine the magnitude of maldistribution inflow that usually takes place in such a design. Four other models have employed with different diameters of the header of 101.6, 76.2 and 50.8 mm and lateral of 50.8, 38.1 and 25.4 mm. These models used for the purpose of testing the stream and pressure allocation based on the AR. Three different values of 625, 790 and 950 l/min from of inlet flows examined with the employed models. The outcomes show that the AR parameter has a notable impact on the consistency of the stream from the manifold in which the uniformity of the flow distribution improves by 76% when the AR decreases from 0.48 to 0.13. It is found that the degree of uniformity of the mass discharge from the laterals is unaffected within tested Reynolds numbers of 50,000–200,000. [ABSTRACT FROM AUTHOR]

Objectives: The aim of the present study is to determine applicability of Cameriere's and Drusini's methods in Western Indian population. Methodology: Panoramic radiographs of total 300 Gujarati individuals, equally divided into four study groups were studied by two investigators. The pulp/tooth area ratio (AR) were calculated for maxillary and mandibular canines and tooth coronal indexes (TCI) i.e., the ratio between coronal pulp cavity height and crown height were calculated for mandibular premolars and first and second molars. The acquired data were subjected to correlation and regression analysis and also inter and intraobserver reliability was obtained for both the investigators. Results: The ARs and TCIs for all the respective teeth were significantly correlated with the age of the individuals. The individual regression formulae were derived for all the teeth and were then used separately to calculate the age. There was no statistically significant difference between the mean chronological age and mean calculated age for all the teeth.(P > 0.05). The mean absolute errors for all the teeth were <10 years. Conclusion: The findings of this study prove the applicability of Cameriere's and Drusini's age estimation methods for Western Indian population. However, the weak correlation coefficients suggest the need for further studies to get more accurate results. [ABSTRACT FROM AUTHOR]

Galvanic corrosion at the joint of AZX611 magnesium (anode) and A6N01 aluminum (cathode) in 1 mass% NaCl solution with different cathode/anode area ratios was evaluated. The galvanic potential was different depending on the area ratio. The anode galvanic current density increased with increasing the area ratio. Anode and cathode weight loss corrosion rates, and the average of anode current densities, were linearly related to the logarithm of the area ratio with different slopes. Scanning vibration electrode technology (SVET) has exhibited the presence of anode current spots that increased with the area ratio. Surface profile of the galvanic joint was in good agreement with the SVET results. The obtained effect of cathode/anode area ratio was analyzed by the mixed potential theory. Finally, the compatibility of magnesium/aluminum joint was compared with other dissimilar metal joints. [ABSTRACT FROM AUTHOR]