Behavior Of Modes Research Articles

Phase Behavior and Rational Development Mode of a Fractured Gas Condensate Reservoir with High Pressure and Temperature: A Case Study of the Bozi 3 Block

The Bozi 3 reservoir is an ultra-deep condensate reservoir (−7800 m) with a high temperature (138.24 °C) and high pressure (104.78 MPa), leading to complex phase behaviors. Few PVT studies could be referred in the literature to meet such high temperature and pressure conditions. Furthermore, it is questionable regarding the applicability of existing condensate production techniques to such a high temperature and pressure reservoir. This study first characterized the phase behavior via PVT experiments and EOS tuning. The operating conditions were then optimized through reservoir numerical simulation. Results showed that: (1) the critical condensate temperature and pressure of Bozi 3 condensate gas were 326.24 °C and 43.83 MPa, respectively; (2) four gases (methane, recycled dry gas, carbon dioxide, and nitrogen) were analyzed, and methane was identified as the optimal injection gas; (3) gas injection started when the production began to fall and achieved higher recovery than gas injection started when the pressure fell below the dew-point pressure; (4) simultaneous injection of methane at both the upper and lower parts of the reservoir can effectively produce condensate oil over the entire block. This scheme achieved 8690.43 m3 more oil production and 2.75% higher recovery factor in comparison with depletion production.

Substance use and risk behaviour patterns among people who inject drugs

Abstract Background Substance use and injecting drug use in particular are related to health damages, reduced quality of life and life expectancy. Injecting drug use is a risk factor for acquiring infectious diseases among people who inject drugs (PWID). The aim of the study was to assess the risk behavior related to the use of intravenous psychoactive substances among PWID in Lithuania. Methods In 2023 a cross sectional study using respondent driven sampling (RDS) of active intravenous drug users (n = 370) was conducted in 5 different sites across Lithuania. RDS is a sampling methodology based on peer-referral in underserved populations that cannot be sampled randomly. Descriptive statistical and regression analyses were conducted using SPSS 23.0. Results 78% of the sample were males, 22% - females. Age mean is 40.6 years, SD-7.7. The first injecting drug was used at the age of 18 (mode). 69% of PWID received drug dependance treatment at least once in life. 70% of the PWID in harm reduction services are also in the substitution therapy programmes. Fentanyl is the main substance for every second respondent which is injected 3 times a day and commonly used with alcohol (64%). 79% of PWID during the last injection used sterile needles and syringes. 45% of respondents reported overdosing during the last 12 months and half of all PWID had naloxone for death prevention. Nearly 70% were tested for TB and syphilis during the last 12 months. Conclusions PWID are mainly males who began injecting drugs at 18 years. Unsafe injecting behaviour (frequency and mode), using alcohol were related to lower participation in health care services for PWID. Main messages • Lower participation in health care services is related to behavioural risk factors. • Ongoing research is needed to assess the factors determining engagement into healthcare of PWID.

Unveiling non-monochromatic modes and nonlinearity in Piet Hein quantum semiconductor waveguides

We investigate the propagation characteristics of transverse electric (TE) and transverse magnetic (TM) modes in a semiconductor quantum plasma-filled coaxial waveguide with a Piet Hein cross-section. The unique geometry of the Piet Hein cross-section offers intriguing possibilities for tailoring modal properties and exploiting novel nonlinear phenomena. Using analytical and numerical methods, we unveil the non-monochromatic behaviour of TE and TM modes, characterized by distinct peaks and troughs in their field components. The Ez\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$E_{z}$$\\end{document} component of the TM mode exhibits a suppressed field within the central core and higher concentration in the cladding region, potentially minimizing energy loss within the waveguide. The Eρ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$E_{\\rho }$$\\end{document} component exhibits pronounced oscillations near the waveguide boundaries, suggesting constructive and destructive interference patterns. The Eξ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$E_{\\xi }$$\\end{document} component displays a non-monotonic behaviour with multiple pits and bumps, highlighting the interplay between the TE mode, the Piet Hein geometry, and the semiconductor quantum plasma properties. The Bρ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$B_{\\rho }$$\\end{document} component of the TM mode exhibits a non-monochromatic behaviour with multiple maxima and minima, attributed to the complex interactions between propagating waves with different phase shifts. The Bξ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$B_{\\xi }$$\\end{document} component exhibits a non-uniform distribution with distinct pits and bumps, with a resurgence towards the waveguide edges potentially due to higher-order mode contributions and local field enhancement effects. Our findings pave the way for the development of novel photonic devices with enhanced functionalities based on Piet Hein semiconductor quantum plasma waveguides.

Mediating effects of child schema mode in the relationship between negative parent-child relationships in childhood and non-suicidal self-injurious behavior in college students

This study was aimed to investigate the psychological mechanisms underlying non-suicidal self-injurious behavior. For this purpose, we hypothesized that dysfunctional child modes act as a psychological mechanism to influence the relationship between negative parent-child relationships in childhood and current cognitions (catastrophizing), emotions (emotional dysregulation and depression), and behaviors (non-suicidal self-injurious behaviors). A sample of 430 college students (male 97, female 333) with experience of non-suicidal self-injurious behavior was selected to test the multi-mediation effects of child schema mode (angry, impulsive), catastrophizing, emotional dysregulation, and depression on the relationship between negative parent-child relationships in childhood and non-suicidal self-injury. As a result of structural equation modeling analysis, it was found that negative parent-child relationships in childhood directly influenced child schema mode, catastrophizing, depression, and non-suicidal self-injurious behaviors. In addition, it was found that negative parent-child relationships in childhood were dually mediated by child schema mode and depression and child schema mode and emotional dysregulation. The present study highlights the mediating role of child schema modes as a psychological mechanism underlying the relationship between negative parent-child relationships in childhood and non-suicidal self-injurious behavior. Based on these findings, the usefulness and direction of schema therapy interventions in the field of non-suicidal self-injury counseling are discussed.

Load transfer behavior of 3D printed concrete formwork for ribbed slabs under eccentric axial loads

3D printed concrete (3DPC) has primarily been used for non-structural applications, with limited exploration into its potential for structural load-bearing applications. This is mainly due to the layered structure of 3DPC and the lack of compatibility of conventional reinforcement strategies to be integrated within the 3D concrete printing process. The post-tensioning of 3DPC structures presents an effective solution to improve the load-carrying capacity and cracking behavior of 3DPC. However, understanding the load transfer behavior and failure modes of 3DPC structures under a particular post-tensioning configuration are crucial to determine the permissible post-tensioning load for a structure without premature failure and to understand the distribution of stresses within the concrete structure under post-tensioning loads. The current study aims to investigate the load transfer behavior and failure mode of a 30 mm thick 3DPC formwork designed for one-way ribbed slabs when subjected to end-anchorage post-tensioning. For this purpose, a series of mechanical characterization and load transfer experiments were conducted on ribbed 3DPC formwork. The mechanical characterization investigations involved examining the compressive and flexural strength, as well as the elastic modulus of 3DPC, under various loading orientations relative to the print path. In the load transfer experiments, the end anchorage post-tensioning system was simulated by applying the axial load to the specimen via end plates bonded to the specimen. The variable parameters of the load transfer experiments were the boundary conditions, the eccentricity of the axial load from the neutral axis, and the topology of the ribbed 3DPC formwork. A digital image correlation system was used to study the axial and transverse strain evolution during the load transfer experiments. The experimental results showed that, regardless of the eccentricity of the applied load, the ribbed 3DPC formwork specimens exhibited higher axial load capacity when the load was applied near the bottom flange rather than the top flange. This was because of the reduced effective cross-sectional area for compression when the load was positioned near the top flanges, a consequence of the selected formwork topology, where top flanges were discontinuous to allow for pouring of the cast concrete within the formwork.

In the arm-in-cage test, topical repellents activate mosquitoes to disengage upon contact instead of repelling them at distance

Topical repellents provide protection against mosquito bites and their efficacy is often assessed using the arm-in-cage test. The arm-in-cage test estimates the repellent’s protection time by exposing a repellent-treated forearm to host-seeking mosquitoes inside a cage at regular intervals until the first confirmed mosquito bite. However, the test does not reveal the repellents’ behavioural mode of action. To understand how mosquitoes interact with topical repellents in the arm-in-cage test, we used a 3D infrared video camera system to track individual Aedes aegypti and Anopheles stephensi females during exposure to either a repellent-treated or an untreated forearm. The repellents tested were 20% (m/m) ethanolic solutions of N, N-diethyl-meta-toluamide, p-menthane-3,8-diol, icaridin and ethyl butylacetylaminopropionate. All four repellents substantially reduced the number of bites compared to an untreated forearm, while the flight trajectories indicate that the repellents do not prevent skin contact as the mosquitoes made multiple brief contacts with the treated forearm. We conclude that, in the context of the arm-in-cage test, topical repellents activate mosquitoes to disengage from the forearm with undirected displacements upon contact rather than being repelled at distance by volatile odorants.

An Impact Assessment of Cordon Pricing Relaxation on Modal Shift During the COVID-19 Pandemic

ABSTRACT The COVID-19 pandemic brought significant disruptions to transportation patterns worldwide, with a notable increase in Private Vehicle (PV) usage. Many studies have focused on travel restrictions, while neglecting to consider potential changes in transportation-related policies implemented during COVID-19 that may have improved public health. The present study explores the motivations for modal shifts to PVs and tries to analyze which of the risks of exposure and modifications in transportation policies has caused these modifications. Focusing on the case study of Tehran, Iran, where cordon pricing was relaxed during the pandemic, the study collected data through online and paper-based surveys from 1475 respondents. Binary logit models were employed to analyze the data and understand the impact of destination location, residency area, trip purpose, trip frequency, and vehicle characteristics on modal shift behavior. In addition to COVID-19 exposure as a primary reason for the modal shift, respondents also identified the relaxation of cordon pricing restrictions as a factor that increased the utility of PVs. The study's findings contribute to better understanding the dynamics of travel behavior during pandemics, guiding policymakers in devising effective strategies to address both public health concerns and traffic conditions.

Study on dynamic post-buckling stability of fast reactor vessels subjected to vertical vibration

Abstract As a lesson learned from the Fukushima nuclear accident, the importance of accident mitigation for Beyond Design Basis Events (BDBEs) is recognized. Excessive earthquake is a typical BDBE. During such events, the Fast Reactor Vessel (FRV) is vulnerable to buckling. The safety goal of FRV under excessive earthquake is to achieve a stable post-buckling state. Our previous study on bending buckling confirmed a global response stability under horizontal vibration. As a parallel study, this paper focuses on axial compression buckling under vertical vibration. Shaking table experiments using thin-walled cylindrical models (R/t=260) are carried out. Similar methodology is applied to investigate the buckling and post-buckling behavior. It is found that axial compression buckling shares an extensive similarity with bending buckling in both buckling mode and post-buckling behavior. Similar global response stability is confirmed due to phase-inverse phenomenon. After buckling, buckling failure becomes stable and does not progress further even when an intense input amplitude is continuously applied. The vibrational load acts as a displacement-controlled load in the out-of-phase domain such that immediate collapse is prevented. Most input energy is dissipated in hysteresis loops rather than being carried by the mass. These mechanisms are independent of input waveform and can be applied to an arbitrary seismic input. In addition, a conservative limit displacement for global response stability is identified. Moreover, the effect of the input frequency ratio, the initial geometrical imperfection and the gravitational force on the post-buckling behavior are clarified.

Analysis of behavior and uniaxial compression failure modes in ungrouted hollow concrete block masonry and their implication in design expressions

In this study, new analytical expressions for the design and revision of ungrouted masonry of hollow concrete blocks under gravitational effects were developed. These expressions can predict the compressive strength and modulus of elasticity for full and face-shell mortar beddings. A trend chart was generated, considering various modes of failure for different strength relationships between blocks and mortar. The study revealed that the main international masonry design codes underestimate the compression resistance of masonry when using weak mortar in combination with full mortar bedding. Results obtained using the Finite Element Method indicated that the optimal compression strength ranges were: 62–70 % for weaker mortar than the block with full mortar bedding; 152 % for block weaker than the mortar with full mortar bedding; and close to 67 % with face-shell bedding mortar.

Numerical Study on the Retrofitting of Exterior RC Beam-column Joints with CFRP Composites Using the Grooving Method

Retrofitting seismically deficient beam-column joints (BCJs) in reinforced concrete (RC) structures is crucial to preventing collapse during high-intensity earthquakes. Fiber reinforced polymer (FRP) composites have proven effective for retrofitting these components, but debonding of the FRP from concrete surfaces remains a challenge. Recently, the grooving method (GM) has emerged as a promising solution to mitigate this issue, enhancing the bond between FRP and concrete. This paper presents a numerical investigation of BCJs retrofitted with FRP composites using the GM, focusing on various design parameters. The study utilized finite element models developed in ABAQUS, incorporating the concrete damage plasticity (CDP) model to simulate the nonlinear behavior of concrete. The interface between the concrete and FRP was modeled as a perfect bond, simulating the strong adhesion provided by the GM. The numerical results were validated against experimental data from two BCJ specimens, showing good agreement in terms of load-displacement behavior, peak loads, and failure modes. Key parameters studied include the beam longitudinal reinforcement ratio, column axial load ratio, and joint aspect ratio. The findings reveal that these parameters significantly affect the shear capacity of retrofitted joints, impacting the efficiency of the retrofitting.

Fatigue life prediction of film-cooling Hole specimens with initial damage

This study investigates a Nickel-based single crystal (SX) superalloy with femtosecond laser-drilled film-cooling holes (FCHs) under varying temperatures (room temperature, 850 °C, and 980 °C), employing a novel framework for predicting fatigue life based on initial manufacturing damage quantification. For all tested anisotropic SX superalloy specimens (including smooth and FCH specimens), the initial damage state is characterized as an equivalent initial flaw size (EIFS), and an EIFS calculation model considering stress concentration is established. Subsequently, the fatigue crack paths and microstructural characteristics of the FCH specimens at different temperatures are analyzed, elucidating crack initiation mechanisms and propagation patterns. A novel incremental plasticity J-integral driving force for fatigue crack propagation is introduced. By incorporating the closure effect of small crack propagation and employing Markov Chain Monte Carlo simulations for determining crack growth rate probabilities, a more accurate expression for the crack growth rate in relation to ΔJfat − ΔJth is derived. This expression comprehensively captures crack patterns on crystallographic planes and Type I mixed mode behavior. Finally, the total fatigue life of the FCH structures, featuring a threefold dispersion zone in both room and high-temperature environments, is predicted through experimental observations and description of crack growth rates. The predicted outcomes significantly outperform those of the conventional life prediction models reliant on crystal plasticity theory.

Metabolic rate and foraging behaviour: a mechanistic link across body size and temperature gradients

The mechanistic link between metabolic rate and foraging behaviour is a crucial aspect of several energy‐based ecological theories. Despite its importance to ecology however, it remains unclear whether and how energy requirements and behavioural patterns are mechanistically connected. Here we aimed to assess how modes of behaviour, including cumulative space use, patch selection and time spent in an experimental resource‐patchy environment, are related to a forager's standard metabolic rate (SMR) and its main determinants, i.e. body mass and temperature. We tested the individual behavioural patterns and metabolic rates of a model organism, the amphipod Gammarus insensibilis, across a range of body masses and temperatures. We demonstrated quantitatively that body mass and temperature exert a major influence on foraging decisions and space use behaviour via their effects on metabolic rates and the marginal value of energy. Individual cumulative space use was found to scale allometrically with body mass and exponentially with temperature, with patch giving‐up time falling as body mass and temperature increased. In response to warmer temperatures, the specimens adaptively intensified their foraging effort and explored larger spaces to offset the elevated SMR. Our results showed that SMR explained more variation than body mass and temperature combined, and had greater predictive power for behavioural patterns. Furthermore, foraging decisions regarding patch choice and partitioning were strongly related to mass‐and‐temperature‐adjusted SMR (residual), which is a component of metabolic phenotype. Individuals with higher M–T adjusted SMR initially preferred the most profitable patch and, as time progressed, abandoned the patch earlier and explored more space than the others. These results demonstrate that foraging decisions are intimately associated with variations in standard metabolic rate, whether phenotypic or due to size and temperature combined. This, in turn, sheds light on higher‐order energy‐based ecological processes.

Ultrafast spectroscopy of coherent phonons across the pressure driven insulator to metal phase transition in V2O3

Nowadays, materials science is moving towards the understanding and control of materials in nonequilibrium states by making use of perturbative techniques to investigate their dynamical responses. From this perspective, the use of ultrashort light pulses seems to be a relevant approach as it can selectively address different degrees of freedom in solid-state systems and more particularly electrons. Such a method can help to decipher the physical phenomena arising from electronic correlations and complements a more conventional methodology where the phase diagrams of materials are investigated at thermodynamical equilibrium. Here, we combine femtosecond optical spectroscopy and a high-pressure setup to monitor the ultrafast out-of-equilibrium photo response of a V2O3 thin film across the pressure driven insulator-to-metal transition. The experimental results demonstrate the possibility to use the spectroscopy of coherent phonons as a thermodynamical phase marker in V2O3 thin films. In addition, the frequency behavior of the ultrafast coherent phonon mode (A1g character) seems to reflect the manifestation of a strong coupling between the lattice and electronic degrees of freedom near first-order transition lines with a pronounced drop in frequency around the critical pressure. Published by the American Physical Society 2024

Seismic behavior and failure analysis of prefabricated foamed concrete composite walls for passive houses

In view of the lack of research on the failure mode and seismic behavior of high-performance insulation walls utilizing lightweight concrete as the structural material, this study presents experimental findings from a seismic behavior investigation of prefabricate foamed concrete composite walls (PFCCWs) for passive house in China. The PFCCWs incorporate low thermal conductivity and high-strength foamed concrete, polyurethane, decorative magnesium straw slabs to provide excellent thermal and mechanical properties for prefabricated passive houses in hot summer and cold winter area. The seismic behavior of PFCCWs under different influence factors were elaborated using quasi-static test data and observation of external damage. The lightweight and porous nature of foamed concrete leads to significant crack formation during failure. The findings suggest that the skin effect of magnesium straw slabs and polyurethane impedes crack development and improve the load-bearing capacity with ductility enhancement. Additionally, reducing the aspect ratio and substituting post-cast column concrete with common concrete are effective to improve the seismic behavior. The window opening changes the worst damage area of the wall and notably weakens the seismic behavior. The enhanced integrity of cast-in-place wall leads to the difference in the failure mechanism and increases in load-bearing and deformation capacities. Meanwhile, design suggestions for the foamed concrete insulation walls are also proposed by comparing the failure mode and hysteretic response of various wall types.

Ultimate strength assessment of randomly pitted stiffened panels considering stiffener corrosion

Stiffened panels are renowned for their exceptional load-bearing capabilities due to their high strength-to-weight ratio and are extensively utilized in ship and marine structures. Nevertheless, they are susceptible to failure under compression, particularly in marine environments where corrosion leads to material and structural degradation. Stiffener corrosion was not involved adequately in current studies, with an unclear synergistic effect of corrosion damage with structural configurations. This paper introduces a numerical modeling approach to develop finite element (FE) models of panels with random pitting corrosion, considering both corrosion on the plating and stiffeners. These FE models are validated against existing experiments and empirical formulae and employed to investigate the effect of random pitting damage on the ultimate strength of panels. The study examines the impact of various structural parameters, such as plate aspect ratio, plate slenderness ratio, stiffener slenderness ratio, and the height-to-thickness ratio of stiffener web, on ultimate strength under different levels of pitting damage. Additionally, the load-bearing behavior and failure modes of damaged panels are analyzed. An artificial neural network (ANN) is developed to predict the ultimate strength of pitted panels. The findings indicate that the ultimate strength of panels with stiffener corrosion in the form of random pitting corrosion leads to a more significant reduction by about 17.7% than that without stiffener corrosion, potentially altering the failure mode. The proposed ANN model accurately predicts the ultimate strength of pitted panels with and without stiffener corrosion, with a mean relative error of approximately 1.1% compared to FE analysis results.

Modal identification as a tool to increase the accuracy of acoustic absorption measurements in reverberation rooms

Measuring the acoustic properties of materials may be very challenging. At low frequencies, the sample may interfere with the room's modal behavior. When it occurs, the longest modal decays are influenced. Differences in reverberation time - empty Vs with-specimen conditions - are often emphasized by these modal effects, and, as a matter of fact, the absorption coefficient may be overestimated. The present work aims to increase the accuracy through data augmentation at low frequencies. Modal identification was performed on measured impulse responses of porous specimens, allowing the determination of modal-decay times within the third-octave bands of 80-160 Hz. A statistical analysis of natural modes highlights the modes whose decay exceeds the density function as outliers. This preliminary study ultimately provides some statistical considerations on the modal distribution of decay times and their relationship with the reverberation time measured through the Schroeder integral.

Design of lightweight aircraft trim panel with a high sound transmission loss

The trim panels of aircraft cabin are frequently made up of multilayer materials including a honeycomb, typically in the form of sandwich panels, which have the advantage of being lightweight and space-saving, but lack good acoustic insulation. It has been shown that, for 10% more mass, weights arranged in a fractal pattern in the honeycomb affect the vibratory pattern of a sandwich panel by creating multiple reflections of the bending waves on the inclusions. They thus generate a phenomenon of focusing vibratory waves providing localized modes while attenuating the structure's acoustic radiation. The objectives of this paper are to describe: first, the vibro-acoustic model of an overloaded homogenized bending panel (to mimic a trim panel with a fractal pattern); second, the physical phenomena associated to this concept; third, the impact on the modal behavior and the vibratory and acoustic responses.

Higher-order nonlinear modeling and multi-modal performance of axially restrained diverse flexible shaft-disk assemblies

Flexible shaft-disk combinations are essential in engines, turbines, and machinery. Understanding their modal characteristics is vital for industry-wide performance, reliability, and safety. This study uses higher-order modeling and multi-modal analysis to grasp complex dynamics, especially with multiple disks of varied sizes. Employing Hamilton’s method and Galerkin’s technique, equations of motion are formulated and then utilized for multi-modal analysis considering structural nonlinearity. Various shaft-disk arrangements are analyzed, including disk number, size, position, and shaft material, to understand their impact on modal behavior. The findings reveal the substantial impact of disk count, sizes, and placements on modal dynamics and intricate vibration characteristics across diverse spinning speeds. This effect is accentuated by integrating higher-order modeling into multi-modal analysis. Notably, higher-order deformation enhances overall resilience capacity and imposes more effective vibration restrictions than the linear approach. Furthermore, the investigation explores how different shaft materials influence modal characteristics, critical speeds, and vibration amplitudes in various shaft-disk combinations. Theoretical findings are validated using numerical results from 3D finite element-based models simulated with ANSYS 3D for accuracy. Ultimately, the study introduces a theoretical framework adaptable to numerous flexible shaft-disk combinations, offering a valuable resource for understanding and enhancing system behavior, benefiting engineers and researchers alike.

Variability of low frequency laboratory measurements of acoustic isolation of floor/ceiling assemblies

It has long been recognized that building acoustics measurements performed in laboratories exhibit a high degree of variability between and within labs. Traditional metrics limited the use of data to above the 100Hz or 125Hz one-third octave bands. In recent years, focus has widened the range of frequencies of interest to the 50Hz one-third octave band or lower. Analyzing measurements of low frequencies in buildings is complicated by the physical reality of wavelengths that are similar in scale to common room dimensions resulting in modal behavior and the mathematical simplification of the wave equation in building acoustic calculations that assumes a diffuse field which discounts both phase and angle of incidence. Evaluation of common building isolation measurements of the same test floor/ceiling structure sample in the same lab and between labs across the frequency spectrum allows the comparison of the repeatability and reproducibility at low frequency ranges to those at high frequency ranges. Measurements and their associated metrics of various sources, including pink noise produced by loudspeakers, the standard tapping machine, and the impact ball are included in the analysis.

Topological protection revealed by real-time longitudinal and transverse transport measurements

Topology is essential for achieving unchanged (or protected) quantum properties in the presence of perturbations. A challenge facing the application is the variable protection levels displayed in real systems associated with the reconstructive behaviors of the dissipationless modes. Despite various insights on potential causes of backscattering, the edge-state-based approach is incomplete because the bulk states also contribute indispensably. This study investigates sample-scale reconstruction where dissipationless modes are global objects instead of being restricted to the sample edge. An integer quantum Hall effect hosted in a Corbino geometry is adopted and brought to the verge of a breakdown. Two independent and simultaneous detections are performed to capture transport responses in both longitudinal and transverse directions. The real-time correspondence between orthogonal results confirms two facts. 1. Dissipationless modes undergo frequent reconstruction in response to electrochemical potential changes, causing dissipationless current paths to expand transversely into the bulk while preserving chirality. A breakdown only occurs when a backscattering emerges between reconstructed dissipationless current paths bridging opposite edge contacts. 2. Topological protection is subject to an interplay of disorder, electron-electron interaction, and topology. The proposed reconstruction mechanism qualitatively explains the robustness variations, beneficial for protection optimization.