Restricted Space Research Articles

Pedestrian Collision and Future Work in the Restricted Indoor Space: A State-of-the-art Review on Influencing Factors, Behaviors and Methods

Abstract Emergency evacuation involves rapidly transferring of individuals from hazardous areas, where limited time and space can lead to collisions. Although previous researchers have studied the collision behavior of evacuees, there is a lack of systematic summary. This work uses CiteSpace visualization software to analyze the keywords in evacuation collision literature. Based on the frequency of keyword occurrence, we determine the research trend, classify the keywords, and analyze and summarize their influencing factors, behavioral characteristics, and research methods. Obviously, the evacuation environment and emergency guidance directly affect individual behavior and emotions, mainly affecting gait adjustment and decision-making processes, which in turn determine evacuation efficiency and collision risk. In the future, emphasis should be placed on post-collision psychological activities, coping strategies, and the application of virtual and mixed reality technologies to observe the interaction between individuals and the environment and strengthen evacuation research.

Life space restriction following disruptive life events: Evidence from the COVID-19 pandemic.

Restriction of life space mobility is associated with adverse health outcomes including depression, morbidity, mortality and poorer quality of life. In this study, we aimed to determine the impact of COVID-19 and associated employment loss on the life space of older adults in Singapore. An in-person survey was administered to a cohort of older Singaporeans above 50 years old (N = 1,118). Data collected included self-report measures of life space, sensory function, well-being, cognitive function, depression, frailty, and objective measures of muscle mass and body mass index. Tests of association and linear regression were performed to test the hypotheses, while accounting for the effects of health and sociodemographic covariates. The life space of older adults have significantly diminished after the pandemic. This loss remained significant despite controlling for covariates and was more pronounced amongst those who had lost employment during the pandemic. In addition, losing employment during the pandemic was associated with having smaller life spaces. Life space assessments are a potential important noninvasive marker for not only health and longevity, but the ability to sustain employment. Public health crises like the COVID-19 pandemic and employment loss negatively impacts the life spaces of older adults. It is needful to emphasize the maintenance of life space when faced with disruptive life events and provide multidisciplinary collaborative solutions to restore the quality of life amongst vulnerable older adults.

Operating principles of interconnected feedback loops driving cell fate transitions

Interconnected feedback loops are prevalent across biological mechanisms, including cell fate transitions enabled by epigenetic mechanisms in carcinomas. However, the operating principles of these networks remain largely unexplored. Here, we identify numerous interconnected feedback loops implicated in cell lineage decisions, which we discover to be the hallmarks of lower- and higher-dimensional state space. We demonstrate that networks having higher centrality nodes have restricted state space while those with lower centrality nodes have higher dimensional state space. The topologically distinct networks with identical node or loop counts have different steady-state distributions, highlighting the crucial influence of network structure on emergent dynamics. Further, regardless of topology, networks with autoregulated nodes exhibit multiple steady states, thereby “liberating” network dynamics from absolute topological control. These findings unravel the design principles of multistable networks implicated in fate decisions and can have crucial implications in engineering or comprehending multi-fate decision circuits.

Enhancing fire suppression in restricted spaces with fine water mist microcapsules

Enhancing fire suppression in restricted spaces with fine water mist microcapsules

Discrete gas kinetic simulation of characteristics of variable temperature wall driven thermal creep flow in cavity

In order to examine the influence of wall temperature change on the flow and heat transfer properties of rarefied gas in restricted space, the discrete unified gas kinetic scheme (DUGKS) is used to simulate the thermal creep flows in a square cavity. All the boundaries of the cavity are stationary diffuse reflection walls. The temperature of left wall and right wall are lower, and the temperature of the upper wall and the lower wall are both subjected to periodic variation. The simulation parameters considered in the present work are set as follows: the Knudsen number <i>Kn</i> is in a range 0.01–10, temperature change frequency <i>St</i> in a range of 0.5–5, and temperature change amplitude <i>A</i><sub>h </sub>in a range of 0.1–0.8. The results indicate that the velocity field and temperature field in the cavity exhibit periodic variations. No inverse Fourier heat transfer phenomenon is observed within the parameter ranges studied. The intensity of the thermal creep flow can be increased by increasing the frequency, temperature, and the Knudsen number. This can also raise the temperature jump and velocity slip close to the temperature change walls. Heat transfer lag and a reduction in the heat transfer capability of the wall are caused by increasing <i>St</i> and <i>Kn</i>. When <i>St</i> is small, say, <i>St</i> = 0.5, a complex vortex structure is seen in the cavity. As the value of <i>St</i> rises to 5, the vortex disappears, the gas travels from the variable temperature wall to the horizontal centerline of cavity, and the region close to the middle of the left wall and right wall changes from an endothermic zone to an exothermic zone. Furthermore, the temperature field and velocity field inside the cavity hardly change, but the degree of heat transfer on the wall decreases with the increase of <i>A</i><sub>h</sub>. The main results are shown in the figure attached below. This work provides helpful recommendations for designing the MEMS devices by using pulsed heating.

Modeling the navigating forces behind BSA aggregation in a microfluidic chip.

Microfluidic chips are powerful tools for investigating numerous variables including chemical and physical parameters on protein aggregation. This study investigated the aggregation of bovine serum albumin (BSA) in two different systems: a vial-based static system and a microfluidic chip-based dynamic system in which BSA aggregation was induced successfully. BSA aggregation induced in a microfluidic chip on a timescale of seconds enabled a dynamic investigation of the forces driving the aggregation process. This study employed a combination of experimental approaches, including biophysical and microscopic methods, and computational simulations using MATLAB and COMSOL Multiphysics. Obtained results revealed that Brownian movement, advective mixing, and laminar flow applied in favor of the formation of amyloid-like aggregates through the entire pathway. Furthermore, heating provided the necessary energy for the initial BSA's partial unfolding. In the following, space restriction and the cumulative effects of repulsive electrostatic and attractive van der Waals forces contributed to forming BSA clusters as a partially unfolded intermediate in the first few seconds of the aggregation process. Consequently, the synergistic effects of hydrodynamic forces (including shear force), hydrophobic interaction, and space restriction resulted in the deposition of larger aggregates on the channel sidewalls. Due to the elevated local concentration of BSA clusters alongside the strong shear force toward the channel sidewalls, the deposited structures underwent a structural conversion to form amyloid-like aggregates within a few seconds. In this study, we not only elucidated the molecular mechanisms underlying BSA aggregation but also highlighted the forces driving the aggregation process in microfluidic systems, explaining how it occurs within a timescale of seconds.

Global well-posedness, ill-posedness and long time behavior of solutions of the surface electromigration equation

Abstract This paper is concerned with the Cauchy problem and the long time behavior of the two-dimensional surface electromigration (SEM) equation. Firstly, we prove that the SEM equation is locally well-posed in H s ( R 2 ) with s > − 1 4 , and globally well-posed in L 2 ( R 2 ) without smallness assumption. Secondly, we prove that the SEM equation is ill-posed in H s ( R 2 ) with s < − 1 4 in the sense that the solution map is not C 2. Finally, we get a local energy decay result of the global solution in a growing unbounded in time region but not containing the soliton region. Our well-posedness results extend the latest findings in Linares et al (2021 Nonlinearity 34 5213–33), where the authors proved that the SEM equation is locally well-posed in H s ( R 2 ) with s > 1 2 . The key ingredient in this paper is to rewrite the linear and nonlinear part in the SEM equation into symmetric separate dispersive terms on the two space variables and some divergence form, respectively. After this invertible process, we use two bilinear estimates in the modified Fourier restriction space introduced in Kinoshita (2021 Ann. Inst. Henri Poincare C 38 451–505) to relax the local well-posedness index from s > 1 2 to s > − 1 4 .

Comparing CT-like bone images based on FRACTURE MR with CT in pediatric congenital vertebral anomalies.

Congenital vertebral anomalies are commonly associated with underlying spinal cord anomaly which necessitates imaging both the spinal cord and the bony vertebral column to understand the extent of the deformity better. While MRI is the gold standard for spinal cord imaging, it does not provide CT-like bone details. Many MR bone imaging techniques have been tested in various adult spine conditions in the past decade but not much has been described on their reliability in pediatric spine. We elaborate on our experience with Fast field echo resembling a CT using restricted echo spacing (FRACTURE) MR bone imaging in congenital vertebral anomalies in children. 11 pediatric patients referred to the imaging department for CT and MR study of congenital vertebral anomaly were prospectively included. After receiving informed consent from these patient's guardians, both studies were performed in a single setting and under a single sedation. FRACTURE MR was accelerated using the compressed SENSE technique to reduce the imaging time. We then compared FRACTURE MR and CT images for image quality and studied parameters like formation or segmentation anomalies, anomalous shape of vertebrae, and alignment deformities. FRACTURE MR showed acceptable image quality with diagnostically limiting artifacts in only 1 patient. The inter-reader agreement was perfect in the assessment of vertebral body segmentation or formation anomaly and alignment abnormalities, and it was substantial for posterior element anomalies. The bone signal was lower in children under the age of 3 years of age due to a more immature and cartilaginous skeleton. FRACTURE MR provides images of acceptable quality in pediatric spinal anomalies. The addition of this novel sequence can be complementary to conventional MR in providing osseous details and CT can be reserved for certain specific indications like post operative cases. This can help in reducing the radiation dose to this group of pediatric patients who will be serially followed up with imaging during their management. FRACTURE - Fats field echo resembling a CT using restricted echo spacing, CS - Compressed SENSE, KF - Klippel Feil, GRE - Gradient echo, UTE - Ultrashort Time to echo, ZTE - Zero Time to echo, CNR - Contrast-to-noise ratio, SNR - Signal-tonoise ratio, MSK -Musculoskeletal.

Análise Multicritério para Seleção de Técnicas Compensatórias de Drenagem Urbana e Recomendação de sua Distribuição Espacial para a Cidade de Itajubá – MG

Objective - This study evaluated the applicability of the integration of multicriteria analysis methods with Geographic Information System tools to identify suitable locations for the implementation of sustainable drainage measures. Methodology – The multicriteria analysis method known as Analytical Hierarchical Process (AHP) was employed alongside QGIS software to evaluate bioretention, detention basins, permeable pavements, individual reservoirs, and green/storage roofs in a case study conducted in the city of Itajubá, MG. Originality/relevance – Decision-makers continue to face challenges in identifying optimal locations for implementing sustainable urban drainage techniques that account for technical and spatial constraints, posing a persistent barrier to their widespread adoption. Results – It was observed that detention basins are more suitable for peripheral areas and individual reservoirs and green/storage roofs systems for urban areas. Bioretention was not very suitable for urban areas, due to space restrictions. The most influential criterion overall was “solid input”, except for the green/storage roof system, which prioritized the resident population. Social and environmental contributions - This work provides a consolidated methodology for creating maps that can be used by decision makers to choose the most suitable locations for the application of sustainable urban drainage techniques, contributing to the reduction of flooding and diffuse pollution in urban centers.

Instrumenting Parkrun: Usefulness and Validity of Inertial Sensors.

The analysis of running gait has conventionally taken place within an expensive and restricted laboratory space, with wearable technology offering a practical, cost-effective, and unobtrusive way to examine running gait in more natural environments. This pilot study presents a wearable inertial measurement unit (IMU) setup for the continuous analysis of running gait during an outdoor parkrun (i.e., 5 km). The study aimed to (1) provide analytical validation of running gait measures compared to time- and age-graded performance and (2) explore performance validation. Ten healthy adults (7 females, 3 males, mean age 37.2 ± 11.7 years) participated. The participants wore Axivity AX6 IMUs on the talus joint of each foot, recording tri-axial accelerometer and gyroscope data at 200 Hz. Temporal gait characteristics-gait cycle, ground contact time, swing time, and duty factor-were extracted using zero-crossing algorithms. The data were analyzed for correlations between the running performance, foot strike type, and fatigue-induced changes in temporal gait characteristics. Strong correlations were found between the performance time and both the gait cycle and ground contact time, with weak correlations for foot strike types. The analysis of asymmetry and fatigue highlighted modest changes in gait as fatigue increased, but no significant gender differences were found. This setup demonstrates potential for in-field gait analysis for running, providing insights for performance and injury prevention strategies.

General Spin-Restricted Open-Shell Configuration Interaction Approach: Application to Metal K-Edge X-ray Absorption Spectra of Ferro- and Antiferromagnetically Coupled Dimers.

In this work, we present a generalized implementation of the previously developed restricted open-shell configuration interaction singles (ROCIS) family of methods. The new method allows us to treat high-spin (HS) ferro- as well as antiferromagnetically (AF) coupled systems while retaining the total spin as a good quantum number. To achieve this important and nontrivial goal, we employ the machinery of the iterative configuration expansion (ICE) method, which is able to tackle general configuration interaction (CI) problems on the basis of spin-adapted configuration state functions (CSFs). While ICE is designed to work in restricted orbital spaces, the new general-spin ROCIS (GS-ROCIS) method is designed to be applicable to larger molecules by employing a prototyping strategy. This new method can be applied to closed-shell, high-spin open-shell, as well as antiferromagnetic reference CSFs. In addition, GS-ROCIS can be combined with the pair natural orbital (PNO) machinery in the form of the PNO-GS-ROCIS method. With this extension, one can drastically reduce the required virtual space in the vicinity of the involved core orbitals, leading to computational savings of several orders of magnitude with negligible (<1%) loss in accuracy. To demonstrate the use of the new methodology, the metal K pre-edge X-ray absorption excitation problem of an antiferromagnetically coupled copper model dimer was investigated. By first analyzing a model copper dimer, it is shown that even for the minimum core excitation problem that involves the two antiferromagnetically coupled singly occupied orbitals and one virtual orbital, the resulting GS-ROCIS and broken-symmetry configuration interaction singles (BS-CIS) spectra may differ in terms of the number, energy position, and relative intensity of the computed bands. Furthermore, the methodology was validated to perform equally well in computing the K-edge spectra of antiferromagnetic nickel oxide dimers and mixed-valence cobalt oxide trimers. Collectively, the present development represents an important methodological advance in the application of theoretical X-ray spectroscopy.

Exact eigenstates of multicomponent Hubbard models: SU( N ) magnetic η pairing, weak ergodicity breaking, and partial integrability

We construct exact eigenstates of multicomponent Hubbard models in arbitrary dimensions by generalizing the η-pairing mechanism. Our models include the SU(N) Hubbard model as a special case. Unlike the conventional two-component case, the generalized η-pairing mechanism permits the construction of eigenstates that feature off-diagonal long-range order and magnetic long-range order. These states form fragmented fermionic condensates due to a simultaneous condensation of multicomponent η pairs. While the η-pairing states in the SU(2) Hubbard model are based on the η-pairing symmetry, the exact eigenstates in the N-component system with N≥3 arise not from symmetry of the Hamiltonian but from a spectrum generating algebra defined in a restricted Hilbert space. We exploit this fact to show that the generalized η-pairing eigenstates do not satisfy the eigenstate thermalization hypothesis and serve as quantum many-body scar states. This result indicates a weak breakdown of ergodicity in the N-component Hubbard models for N≥3. Furthermore, we show that these exact eigenstates constitute integrable subsectors in which the Hubbard Hamiltonian effectively reduces to a noninteracting model. This partial integrability causes various multicomponent Hubbard models to weakly break ergodicity. We propose a method of harnessing dissipation to distill the integrable part of the dynamics and elucidate a mechanism of nonthermalization caused by dissipation. This work establishes the coexistence of off-diagonal long-range order and SU(N) magnetism in excited eigenstates of the multicomponent Hubbard models, which presents a possibility of novel out-of-equilibrium pairing states of multicomponent fermions. These models unveil a unique feature of quantum thermalization of multicomponent fermions, which can experimentally be tested with cold-atom quantum simulators. Published by the American Physical Society 2024

Life in and out of combat clubs: the experiences of Iranian martial artists

Considering the mechanized modern living in restricted indoor spaces, aggression and mental disorders among young people and adults and their negative consequences in Iran, in-depth studies of this issue are important. The purpose of this article is to understand the meaning of combat sports for Iranian athletes and to understand how it drives them to action. Following an Interpretative Phenomenological Analysis (IPA) approach, 17 male kickboxing and muay Thai athletes in the Kurdistan province in western Iran were surveyed through semi-structured interviews. Four main themes and 12 sub-themes were extracted from analyzing the experiences of the research participants: (1) Increasing existential capacity, (2) cultivating a moral personality, (3) enhancing one’s health and (4) improving one’s lifestyle. Our research suggests that, for these participants, kickboxing and muay Thai have a positive effect in many mental, social and moral dimensions of existence. Moreover, because of the potential positive impact on the individual behavior, these sports are also very effective in reducing societal problems such as hooliganism, destructiveness and vandalism, suicide, inappropriate lifestyle, decline of values and violence.

Research on network interference problems in intelligent manufacturing

Abstract As the smart manufacturing industry continues to grow, ensuring high-quality data transmission has become especially critical. In wireless communication networks, numerous sources of interference exist, especially significant in restricted space environments such as factories. These areas are subject to signal interference from same-frequency devices and interference from multipath propagation due to signal reflection in buildings. In order to guarantee the communication quality of smart manufacturing systems, reducing network interference in such spaces is a prerequisite; therefore, it becomes crucial to reduce various network interferences. In this study, a scheme combining orthogonal frequency division multiplexing (OFDM) and multiple-input multiple-output (MIMO) techniques is proposed to cope with the interference problem of the network in the smart manufacturing process.

Role of extra-framework aluminum species within MOR zeolites for syngas conversion via OXZEO catalysis

The location of aluminum within the framework or extra-framework of zeolites is a critical factor in determining its catalytic performance. Despite extensive research on the identification and formation mechanism of extra-framework aluminum (EFAl), its impact on catalytic performance requires further investigation. Herein, mordenite (MOR) zeolites with comparable acid density within the 8MR and 12MR channels but different EFAl contents were prepared, and their catalytic roles were examined in syngas conversion. Intelligent gravimetric analysis, model experiment of ethylene conversion and thermogravimetric analysis demonstrate that the existence of EFAl species can inhibit the secondary conversion of ethylene to long chain hydrocarbons (i.e., C5+) as well as the over-accumulation of carbonaceous species. However, excessive EFAl species lead to rapid deactivation due to restricted space and thus severe diffusion limitation. MOR zeolite with a moderate amount of EFAl species achieves a superior ethylene selectivity and exhibits an enhanced stability in syngas conversion when combined with ZnAlOx oxide. The insights gained in this work provide important guidance for the design of more efficient zeolite-based catalysts.

Efficacy of Novel Digital-Based Surgical Guide in the Limited Interocclusal Distance.

Accurate implant placement is essential for achieving successful outcomes. To aid in this, digitally designed surgical guides have been introduced. Both closed-sleeve and open-sleeve designs are commonly utilized. However, the closed-sleeve design has limitations with restricted interocclusal distance, interference with irrigation, and limited visibility, while the open-sleeve design is known to be less accurate. To address these limitations, a new slope-sleeve design was introduced. This design reduces the interocclusal distance requirement compared to the closed-sleeve design and provides improved accuracy. A constraint model with a 31 mm interocclusal distance was created, and three types of surgical guides (closed, open, and slope), printed using either a PolyJet or Digital Light Processing (DLP) 3D printer, were tested on resin bone blocks. Horizontal and angular deviations were measured for the accuracy of each guide after drilling, with data analyzed using one-way ANOVA and independent t-tests. The slope-sleeve design showed significantly lower horizontal and angular deviations in wide-sized guides. Additionally, PolyJet-printed guides showed higher accuracy compared to DLP-printed guides. The slope-sleeve guide offers enhanced stability and precision in restricted interarch spaces. When coupled with high-precision 3D printing technologies like PolyJet, the slope-sleeve design provides a reliable solution for improving implant placement accuracy in challenging clinical scenarios.

A wide-frequency triboelectric vibration sensor for self-powered machinery health monitoring

Abnormal vibration is usually a precursor to structural damage and performance degradation industrial equipment and transportation. Vibration detection at critical locations such as electrical motors and bearings within large equipment has emerged as an indispensable method for machinery health monitoring. Current vibration detection instruments mostly need to be powered by cables or batteries, which has application limitations in complex moving equipment and restricted space. In this paper, a disc-like triboelectric nanogenerator (DL-TENG) with a multi-sized honeycomb structure is proposed as an innovative solution for achieving wide band and high precision acceleration detection of the vibration. Multi-diameter polytetrafluoroethylene (PTFE) balls are used as friction materials to achieve the high voltage output of the TENG, providing sufficient energy for the detection circuit. By carefully designing suitable honeycomb structures for PTFE balls of different diameters, the ability to detect broadband vibration signals is obtained. The experimental results demonstrate that DL-TENG with honeycomb structure and multi-size PTFE balls can detect acceleration signals ranging from 10 to 2000 Hz, and the acceleration measurement range can reach 1–11 m/s2 with an acceleration resolution of 0.1 m/s2. Moreover, DL-TENG can output more than 80 V peak-to-peak under vibration conditions of 11 m/s2. And under vibration conditions of 8 m/s2, the DL-TENG can fully charge a 100 μF capacitor to 5 V in just 100 seconds. By equipping a special circuit for DL-TENG, wireless self-powered vibration detection is realized. This study is expected to be applied in the scenario of vibration information collection in complex ring vibration environment and provides a new paradigm for the realization of self-powered vibration sensors.

Comparative analysis of C moments using different phenomenological models

Analysis of normalized C moments of multiplicity distribution calculated from the different phenomenological models, the Bialas-Praszalowics (BP) model, modified negative binomial and the superposed shifted Gompertz distribution at different center of mass (cms) energies is presented. The analysis covers a range of energies (200–900 GeV) of p¯p collisions in restricted phase space slices. A comparison of different models to the experimental data on charged particle multiplicity spectra from the p¯p annihilation in five pseudorapidity windows is reported. The comparison shows that the two approaches other than the BP model are in better agreement to the data. Results on variation of moments with pseudorapidity window size and with center of mass energy and observations from such a study in p¯p annihilation and pp interactions at the same center-of-mass energy are also presented. Published by the American Physical Society 2024

Bubble Evolution and Its Effects on Methane Hydrate Formation in a Restricted Space

Bubble Evolution and Its Effects on Methane Hydrate Formation in a Restricted Space

Suppression of clock-jitter noise and laser phase noise in arm locking

Abstract Arm-locking technique has been a focus of attention as one of the means to suppress the laser phase noise in space-based gravitational wave detector. The main idea of the arm-locking technique is to transfer the stability of the detector arm length to laser frequency by introducing a feedback control loop. Generally, laser phase noise will be suppressed by an amount similar to the magnitude of the controller gain. However, on the one hand, clock-jitter noise and optical bench motion noise, as the noise floor of the arm-locking technique, need to be suppressed. On the other hand, limited by the Doppler frequency pulling, the gain of the controller generally cannot be too large. It means that even if we do not consider clock-jitter noise and optical bench motion noise, it is difficult to suppress laser phase noise below the noise floor only by arm-locking technique. In this work, we combine self-referenced optical frequency combs and arm-locking technique to generate clock signals that are coherently referenced to the closed-loop laser beams, so that the clock-jitter noise is also suppressed by about the level of controller gain. We conduct a simulation on the above configuration, and the results show that the performance of the arm-locking is no longer limited by clock-jitter noise in the low-frequency band. To address the issue of insufficient laser phase noise suppression by the arm-locking technique, we further investigate time-delay interferometry (TDI) combinations under outputs of arbitrary arm-locking configurations. We obtain the equations for eliminating laser phase noise. To ensure that the TDI combinations can directly operate in the time domain, we derive a restricted solution space by assuming a specific form for the solutions.