Compact Form Research Articles

Design and implementation of a high-performance miniaturized multi-layer magnetic shielding spherical shell with minimal pores based on target magnetic field

Achieving the spin-exchange relaxation-free (SERF) state in atomic comagnetometers (ACMs) necessitates a stable and weak magnetic environment. This paper presents the design of a miniaturized permalloy magnetic shielding spherical shell (MSSS) with minimal apertures, tailored to meet these requirements. By employing a combination of analytical solutions and finite element analysis (FEA), we achieved superior magnetic shielding while maintaining a compact form factor. The analytical solution for the shielding factor indicated that a four-layer permalloy sphere shell with optimized air gaps was necessary. A numerical analysis model of the MSSS was developed and validated using COMSOL software, confirming the suitability of the air gaps. The size, shape, and orientation of the openings in the perforated sphere shell were meticulously designed and optimized to minimize residual magnetism. The optimal structure was fabricated, resulting in triaxial shielding factors of 47619, 52631, and 21739, meeting the anticipated requirements. A comparison of simulation results with experimental tests demonstrated the efficacy of the design methodology. This study has significant implications for ultra-sensitive magnetic field detection devices requiring weak magnetic field environments, such as atomic gyroscopes, magnetometers, atomic interferometers, and atomic clocks.

A novel UWB in‐body printed microstrip feed monopole antenna with dual band‐stop capabilities

AbstractThis paper presents an innovative and condensed blueprint for an ultra‐wideband (UWB) printed monopole antenna, aiming to augment bandwidth and achieve dual band‐stop capabilities, all while accounting for the impact of the human body model on stop bands. The proposed design showcases a square radiating patch situated on the top layer of the substrate, complemented by a ground plane etched on the underside, integrating two sets of adapted U‐shaped slots. Such a configuration delivers a broad operational fractional bandwidth that surpasses 132%. Within our design, a modified C‐shaped slot in the radiation patch creates the first band‐stop property, while a pair of modified F‐shaped slots etched in the radiation patch generates the second stop‐band property. Measuring 12 mm × 18 mm × 0.8 mm, the antenna offers a compact form factor, broad bandwidth, cost‐effectiveness, omnidirectional radiation patterns within the H‐plane and acceptable behavior for using in In‐body microwave applications.

Data-Driven Dynamic Internal Model Control.

A data-driven dynamic internal model control (D3IMC) scheme is proposed for unknown nonlinear nonaffine systems bypassing modeling steps. Different from the traditional internal model constructed by either a first-principle or an identified model, a dynamic internal model (DIM) is developed in this work using I/O data where a compact form dynamic linearization approach is introduced for addressing the nonlinearity and nonaffine structure. Then, the D3IMC is proposed with both a nominal control algorithm and an uncertainty compensation control algorithm. The former can quickly respond to the feedback errors and the latter can compensate the model-plant mismatch and external disturbances. Meanwhile, the adaptive parameter updating law in the proposed D3IMC method inherits the robustness against uncertainties. A nominal D3IMC is also designed without including the compensator when there is no exogenous disturbance since the adaptive mechanism can handle system uncertainty. Further, the results are extended and a full-form dynamic linearization-based D3IMC is developed to address control of nonlinear systems with more complex dynamics. All the proposed D3IMC methods are data-driven without need of an explicit model, and thus they are significant extensions from the traditional model-based IMC. Simulation study verifies the results.

Conformational preferences of cocoa oligomeric proanthocyanidins and their influence on polarity

Proanthocyanidins (OPACs) are the second largest class of plant metabolites after lignans. Although knowledge of their 3D conformations would add greatly to our understanding of their biological properties, very little has been published on the conformations of OPACs with a degree of polymerization (DP) above 4. We investigated the conformations of the linear epicatechin oligomers, prominent representatives of OPACs prevalent in apples and cocoa, where the epicatechin units are interconnected through the 4β-8 bonds. For DP-2 to DP-10 oligomers, conformational preferences reflected in the arrangement of consecutive flavan-3-ol units, are characterized by the φ torsion. For dimers, there are two energy wells corresponding to two preferred φ torsions, designated as compact and extended form. This behaviour is preserved in OPACs with higher DPs, but the most energetically favoured conformations are a combination of both, with compact-only or extended-only conformations being very unlikely. Thus, oligomers with DP ≥ 7 tend to assume an overall conformation approximating a spherical shape. This shape has a significant influence on the polarity of the OPAC oligomers expressed as 3D polar surface area, calculated using Spartan software for geometry-optimized 3D models, and possibly on other physicochemical properties. The results of polarity calculations provide a molecular-level rationale for the polarity-based chromatographic separation of the cocoa B-type procyanidins with DP range 4 to 10. In our experiments, using centrifugal partition chromatography (CPC) (a solvent system consisting of EtOAc-EtOH-water (6:1:5) v/v/v with aqueous phase stationary and upper phase mobile) we found that an enriched mixture of proanthocyanidins eluted first DP-1 (epicatechin) followed by consecutive elution of the DP-2 to DP-10 in the linear 4β-8 form. We demonstrated that such separation would not be possible if compact-only or extended-only conformations were present in solution. However, for the energy-favoured, spherically shaped conformations, the observed CPC elution order is fully justified.

Intra-Urban Induced Heating Assessment in Kuwait’s Desert Metropolis Using Explainable Machine Learning

Intra-urban induced heating (IUIH) in hot desert cities exhibits distinct patterns and complex diurnal interactions with built environment features, differing significantly from those in temperate areas and remains not fully understood. Understanding how various built environment features contribute to intra-urban thermal variability is an essential first step in developing sub-diurnal targeted heat mitigation strategies. This study presents a data-driven examination of IUIH dynamics in Kuwait’s desert metropolis. Near-surface air temperature observations were collected using high-resolution loop-type traverses at selected hours during a representative summer day to determine IUIH variability. The diurnal impacts of built environment features were modeled using an ensemble learning approach and interpreted with SHapley Additive exPlanations. Among several candidate machine learning regressors evaluated, Random Forest demonstrated strong predictive power (R2 = 0.954) with acceptable error (RMSE = 0.096, MAPE = 0.001) and least bias (MBE = 0.008). The study’s significance lies in its assessment framework that emphasizes explainability of sub-diurnal dynamics, offering detailed insights that challenge traditional assumptions and inform both immediate local climate interventions and strategic urban planning. The findings reveal that simple day-evening comparatives might overlook nuanced sub-diurnal dynamics, such as potential irrigation-induced warming by shrubs observed at mid-day and the complex trade-offs between radiative and transpirative processes by trees in the afternoon and evening. Additionally, the study identifies cooling effects associated with natural land cover, presenting a critical optimization challenge between compact and open urban forms to effectively modulate near-surface air temperatures.

Platelet-Type von Willebrand Disease: Complex Pathophysiology and Insights on Novel Therapeutic and Diagnostic Strategies.

von Willebrand disease (VWD) is the most common well-studied genetic bleeding disorder worldwide. Much less is known about platelet-type VWD (PT-VWD), a rare platelet function defect, and a "nonidentical" twin bleeding phenotype to type 2B VWD (2B-VWD). Rather than a defect in the von Willebrand factor (VWF) gene, PT-VWD is caused by a platelet GP1BA mutation leading to a hyperaffinity of the glycoprotein Ibα (GPIbα) platelet surface receptor for VWF, and thus increased platelet clearing and high-molecular-weight VWF multimer elimination. Nine GP1BA gene mutations are known. It is historically believed that this enhanced binding was enabled by the β-switch region of GPIbα adopting an extended β-hairpin form. Recent evidence suggests the pathological conformation that destabilizes the compact triangular form of the R-loop-the GPIbα protein's region for VWF binding. PT-VWD is often misdiagnosed as 2B-VWD, even the though distinction between the two is crucial for proper treatment, as the former requires platelet transfusions, while the latter requires VWF/FVIII concentrate administration. Nevertheless, these PT-VWD treatments remain unsatisfactory, owing to their high cost, low availability, risk of alloimmunity, and the need to carefully balance platelet administration. Antibodies such as 6B4 remain undependable as an alternative therapy due to their questionable efficacy and high costs for this purpose. On the other hand, synthetic peptide therapeutics developed with In-Silico Protein Synthesizer to disrupt the association between GPIbα and VWF show preliminary promise as a therapy based on in vitro experiments. Such peptides could serve as an effective diagnostic technology for discriminating between 2B-VWD and PT-VWD, or potentially all forms of VWD, based on their high specificity. This field is rapidly growing and the current review sheds light on the complex pathology and some novel potential therapeutic and diagnostic strategies.

Enhancing LS-PIE’s Optimal Latent Dimensional Identification: Latent Expansion and Latent Condensation

The Latent Space Perspicacity and Interpretation Enhancement (LS-PIE) framework enhances dimensionality reduction methods for linear latent variable models (LVMs). This paper extends LS-PIE by introducing an optimal latent discovery strategy to automate identifying optimal latent dimensions and projections based on user-defined metrics. The latent condensing (LCON) method clusters and condenses an extensive latent space into a compact form. A new approach, latent expansion (LEXP), incrementally increases latent dimensions using a linear LVM to find an optimal compact space. This study compares these methods across multiple datasets, including a simple toy problem, mixed signals, ECG data, and simulated vibrational data. LEXP can accelerate the discovery of optimal latent spaces and may yield different compact spaces from LCON, depending on the LVM. This paper highlights the LS-PIE algorithm’s applications and compares LCON and LEXP in organising, ranking, and scoring latent components akin to principal component analysis or singular value decomposition. This paper shows clear improvements in the interpretability of the resulting latent representations allowing for clearer and more focused analysis.

Lightwave-electronic harmonic frequency mixing.

Electronic frequency mixers are fundamental building blocks of electronic systems. Harmonic frequency mixing in particular enables broadband electromagnetic signal analysis across octaves of spectrum using a single local oscillator. However, conventional harmonic frequency mixers do not operate beyond hundreds of gigahertz to a few terahertz. If extended to the petahertz scale in a compact and scalable form, harmonic mixers would enable field-resolved optical signal analysis spanning octaves of spectra in a monolithic device without the need for frequency conversion using nonlinear crystals. Here, we demonstrate lightwave-electronic harmonic frequency mixing beyond 0.350 PHz using plasmonic nanoantennas. We demonstrate that the mixing process enables complete, field-resolved detection of spectral content far outside that of the local oscillator, greatly extending the range of detectable frequencies compared to conventional heterodyning techniques. Our work has important implications for applications where optical signals of interest exhibit coherent femtosecond-scale dynamics spanning multiple harmonics.

The Governance of Traffic Noise Impacting Pedestrian Amenities in Melbourne Australia: A Critical Policy Review.

By identifying a unified aim of Federal, State, and Local government authorities to deliver healthier, more liveable urban spaces and enable walkable neighbourhoods in Melbourne, Australia, questions emerge regarding noise data collection methods and the policies that aim to protect pedestrian areas from potential increases in urban traffic noise. It highlights a missed opportunity to develop strategies that provide explicit guidance for designing more compact urban forms without diminishing pedestrian amenities. This study investigates the governance of traffic-induced noise pollution and its impact on pedestrian amenities in Melbourne, Australia. It aims to identify the government bodies best positioned to protect pedestrians from noise pollution and evaluate the strategic justification for reducing traffic noise to enhance urban walkability. This research employs a semi-systematic policy selection method and a hybrid critique and review method to evaluate the multidisciplinary governance frameworks engaged in the management and mitigation of traffic noise in Melbourne. Key findings reveal that while traffic noise poses significant health risks, current policies overlook its impact on pedestrian amenities in urban areas. This study emphasises the benefits of qualitative and subjective noise data collection to inform policy-makers of the pedestrian aural experience and impacts. Discussion points include noise management strategies and the value of implementing metropolitan-scale noise-mapping to illustrate the impact of noise rather than quantities of sound. The conclusions demonstrate that there is strategic justification for managing traffic-induced noise pollution to protect pedestrian areas within international, federal, and state government policies and implicit rationale at a local level.

Phase-stabilised self-injection-locked microcomb

Microresonator frequency combs (microcombs) hold great potential for precision metrology within a compact form factor, impacting a wide range of applications such as point-of-care diagnostics, environmental monitoring, time-keeping, navigation and astronomy. Through the principle of self-injection locking, electrically-driven chip-based microcombs with minimal complexity are now feasible. However, phase-stabilisation of such self-injection-locked microcombs—a prerequisite for metrological frequency combs—has not yet been attained. Here, we address this critical need by demonstrating full phase-stabilisation of a self-injection-locked microcomb. The microresonator is implemented in a silicon nitride photonic chip, and by controlling a pump laser diode and a microheater with low voltage signals (less than 1.57 V), we achieve independent control of the comb’s offset and repetition rate frequencies. Both actuators reach a bandwidth of over 100 kHz, enabling phase-locking of the microcomb to external frequency references. These results establish photonic chip-based, self-injection-locked microcombs as low-complexity yet versatile sources for coherent precision metrology in emerging applications.

Nanopix-v1: A compact miniaturized coded-aperture gamma imager

This article explores the complex challenges associated with detecting and identifying radioactive hotspots in the nuclear industry using gamma cameras. Gamma cameras facilitate the localization of radioactive hotspots by overlaying a visualization of radioactivity onto a visible image. In the nuclear industry, gamma rays are observed in an energy range spanning from 59.5 keV (Am-241) to 1.3 MeV (Co-60).The motivation for this exploration stems from a specific challenge: characterizing hot-cells inaccessible to human operators. At the ORANO La Hague radioactive waste reprocessing plant, access to these restricted regions is possible through apertures with diameters ranging from 8 to 10 cm. In collaboration, the Nanopix-v1, characterized by its compact form as a coded mask gamma imaging system, with dimensions of 8 × 5.1 × 4.3 cm³ and a mass of 268 g, was developed through the synergistic efforts of CEA List and X-ray Imaging Europe (XIE) in partnership with ORANO.This article conducts a detailed examination of the laboratory and in situ performance of the Nanopix-v1, carried out within the challenging operational environment of the La Hague radioactive waste reprocessing plant. The focal point of the article is a comprehensive exploration of the technological components supporting the Nanopix-v1, along with an explanation of the coded mask imaging localization methodologies that underpinned the rigorous evaluation process. The performance of the gamma camera is evaluated through a series of carefully conducted trials, aimed at evaluating the angular resolution and minimum measurement time, including laboratory conditions, experimentation within a metrological Cs-137 irradiator, and practical implementation at the ORANO La Hague site.

Cutting-Edge Microwave Sensors for Vital Signs Detection and Precise Human Lung Water Level Measurement

In this article, a comprehensive review is presented of recent technological advancements utilizing electromagnetic sensors in the microwave range for detecting human vital signs and lung water levels. With the main objective of improving detection accuracy and system robustness, numerous advancements in front-end architecture, detection techniques, and system-level integration have been reported. The benefits of non-contact vital sign detection have garnered significant interest across a range of applications, including healthcare monitoring and search and rescue operations. Moreover, some integrated circuits and portable systems have lately been shown off. A comparative examination of various system architectures, baseband signal processing methods, system-level integration strategies, and possible applications are included in this article. Going forward, researchers will continue to focus on integrating radar chips to achieve compact form factors and employ advanced signal processing methods to further enhance detection accuracy.

Influence of chemical reaction on transient natural convective flow in an infinite vertical cylinder packed with porous material

A study of mass and heat transport on fully developed laminar and transient free convective flow in a vertical cylinder containing a porous substance inside it. The Laplace Transform Method (LTM) is used to solve the governing equations with suitable boundary conditions. A compact form solution represented by using Bessel and modified Bessel functions. The numerical results were thoroughly scrutinized using graphs and tables to illustrate the effects of newly discovered fluid characteristics, including time, Grashof, mass Grashof, Schmidt, Prandtl, Darcy numbers, viscosity ratio on the concentration and the velocity profiles. The velocity and concentration profiles progressively increase with varying time values until reaching a steady state. Furthermore, it is found that the velocity profiles are decreased by the Prandtl, Schmidt number, and viscosity ratio. In contrast, the Darcy, Grashof, and mass Grashof numbers exhibit an opposite effect. The rate of mass transport, skin friction, and mass flux are presented in tables. The major finding of the current research is that the viscosity ratio parameter decelerates the skin friction and mass flux. This study has potential applications in innovative fields such as solar energy systems, chemical engineering processes, etc.

To Be or Not To Be: The Role of Rotation in Modeling Galactic Be X-Ray Binaries

Be X-ray binaries (Be-XRBs) are one of the largest subclasses of high-mass X-ray binaries, comprised of a rapidly rotating Be star and neutron star companion in an eccentric orbit, intermittently accreting material from a decretion disk around the donor. Originating from binary stellar evolution, Be-XRBs are of significant interest to binary population synthesis (BPS) studies, encapsulating the physics of supernovae, common envelope, and mass transfer (MT). Using the state-of-the-art BPS code, POSYDON, which relies on precomputed grids of detailed binary stellar evolution models, we investigate the Galactic Be-XRB population. POSYDON incorporates stellar rotation self-consistently during MT phases, enabling detailed examination of the rotational distribution of Be stars in multiple phases of evolution. Our fiducial BPS and Be-XRB model aligns well with the orbital properties of Galactic Be-XRBs, emphasizing the role of rotational constraints. Our modeling reveals a rapidly rotating population (ω/ω crit ≳ 0.3) of Be-XRB-like systems with a strong peak at intermediate rotation rates (ω/ω crit ≃ 0.6) in close alignment with observations. All Be-XRBs undergo an MT phase before the first compact object forms, with over half experiencing a second MT phase from a stripped helium companion (Case BB). Computing rotationally limited MT efficiencies and applying them to our population, we derive a physically motivated MT efficiency distribution, finding that most Be-XRBs have undergone highly nonconservative MT ( β¯rot≃0.15 ). Our study underscores the importance of detailed angular momentum modeling during MT in interpreting Be-XRB populations, emphasizing this population as a key probe for the stability and efficiency of MT in interacting binaries.

Analysis of axisymmetric thermoelastic diffusive half-space with variable material properties using hyperbolic two-temperature model

The aim of the current study is to investigate the variable thermal conductivity and diffusivity impact on the transient response of an axisymmetric thermodiffusive elastic half-space under axisymmetric thermal, mechanical, and concentration loads in the light of hyperbolic two-temperature generalized fractional thermoelastic diffusion model. With the help of Kirchhoff’s transform, the governing equations are converted into linear form. The resulting equations are solved by imposing the combined Laplace–Hankel transform. In converted space, the solutions for different field quantities are presented in compact form. The copper material is considered for numerical computation. By employing a mathematical inversion procedure, the solutions are converted into the original space. Numerically computed solutions for various physical quantities are illustrated in the form of graphs to show the impact of variable thermal conductivity and diffusivity, hyperbolic two temperature, and fractional parameters. Validation of the obtained results is also presented.

Relational geographies of urban unsustainability: The entanglement of California’s housing crisis with WUI growth and climate change

One of California’s most pressing social and environmental challenges is the rapid expansion of the wildlands–urban interface (WUI). Multiple issues associated with WUI growth compared to more dense and compact urban form are of concern—including greatly increased fire risk, greenhouse gas emissions, and fragmentation of habitat. However, little is understood about the factors driving this growth in the first place and, specifically, its relationship to urban–regional housing dynamics. This paper connects work in urban social science, urban and regional planning, and natural sciences to highlight the potential role of housing crises in driving displacement from the urban core to relatively more affordable exurbs, and with this, WUI growth. We analyze this relationship in California, which leads the nation in lack of affordable housing, scale of WUI growth, and many associated WUI hazards, including wildfire. We offer three related arguments: first, that California’s affordable housing crisis, with its effect of driving migration to exurban areas, should be recognized as a significant urban form-related sustainability challenge; second, that to understand this challenge scholars must expand the spatial scale and analytic toolkit of both urban and WUI analysis through relational, mixed methods research; and third, that political and programmatic efforts to address California’s housing crisis should undergird efforts to address WUI growth and climate change. Ultimately, we argue that expanding access to affordable urban housing can produce a more sustainable and just urban form that mitigates WUI-related climate and environmental impacts and reduces the vulnerability of growing numbers of WUI residents living in harm’s way.

Stochastic switching and analog-state programmable memristor and its utilization for homomorphic encryption hardware

Homomorphic encryption performs computations on encrypted data without decrypting, thereby eliminating security issues during the data communication between clouds and edges. As a result, there is a growing need for homomorphic encryption hardware (HE-HW) for the edges, where low power consumption and a compact form factor are desired. Here, a Pt/Ta2O5/Mo metallic cluster-type memristors (Mo-MCM) characterized by the Mo as a mobile species, and its utilization for the HE-HW via a 1-trasistor-1-memristor (1T1M) array as a prototype HE-HW is proposed. The Mo-MCM exhibits inherent stochastic set-switching behavior, which can be utilized for generating the random numbers required for encryption key generation. Furthermore, the device can accurately store analog conductance states after set-switching, which can be used as an analog non-volatile memristor. By simultaneously leveraging these two characteristics, encryption key generation, data encryption, and decryption are possible within a single device through an in-memory computing manner.

Plastic deformation behavior and energy absorption performance of a composite metamaterial based on asymmetric auxetic lattices

This study focuses on the design, behavior and experimental analysis of a novel metamaterial, consisting of an asymmetric auxetic three-dimensional structure (AATS) infused with polyester resin. Utilizing FDM additive printing, samples were created with customizable responses to compressive loads through varied design parameters. The objective is to surpass traditional material blending by enhancing stiffness and energy absorption. Striking a delicate balance, the AATS energy absorption properties are preserved while leveraging the stiffness of the resin. Despite its compact cubic form, not exceeding 27 mm on each side, this metamaterial showcases amplified characteristics, blending the AATS and polyester resin. The results hint at promising applications across military defense, automotive, aerospace sectors, and even potential replacements for articulated human skeletal components.

Analysis of Urban Form Dynamics in The Suburbs of Surakarta City 2013-2023

Urban Form has become necessary for city planning management to see the sustainability of a city. A better understanding of different urban forms is imperative to facilitate the evolution of cities towards a more sustainable urban development trajectory in the future. The study aims to analyze the dynamics of urban form and the changes in land cover within the peri-urban area of Surakarta City, which is directly influenced by the development of Surakarta City. The analysis was conducted from a landscape ecology perspective, employing a spatial metrics approach at the landscape level to assess the dynamics of urban form using quantitative descriptive, including a spatial approach. A similar approach was adopted at the class level in order to examine the dynamics of land cover changes. The results of the image analysis were validated using the Kappa index, yielding an image accuracy level of 0.86 (86%). The results of this study show that the urban form in the peri-urban area of Surakarta City tends to move towards a compact urban form. Meanwhile, each land cover, vegetation, and water body become increasingly fragmented, with areas becoming narrower as time passes. Built-up and agricultural land are becoming more compact and concentrated along with development. In conclusion, the dynamics of urban form in the peri-urban area of Surakarta City tends to lead to compact urban form.

Application of High-Speed Self-Aligned Focusing Schlieren System for Supersonic Flow Velocimetry

A self-aligned focusing schlieren (SAFS) system combines the field of view of a conventional schlieren system with the defocus blur of a focusing schlieren system away from the object plane. It can be assembled in a compact form, measuring 1.2 m (4 ft) in length in the described case. The depth of field is sufficiently shallow to distinguish specific spanwise features in a supersonic flow field within a 76.2 mm (3 in) wide test section. As a result, the boundary-layer perturbations on windows and window-material defects and surface imperfections are blurred. Analytical forms are derived for depth of field and vignetting of the SAFS system. A laser spark velocity measurement in Mach 2 flow is performed by tracking the blast wave of a laser spark using 500 kHz SAFS imaging with a 200 ns optical pulse width. The flow Mach number and stagnation temperature are measured by comparing the blast-wave dynamics to an analytical solution. Additionally, schlieren image velocimetry is performed by analyzing natural flow perturbations in 500 kHz SAFS images using a self-correlation method. Comparing the spectra of gas density perturbations from the core flow and a near-wall region reveals a significant difference, with high-frequency prevalence at the boundary-layer location.