Compact Form Research Articles

Exploring the Impact of Different Milling Parameters of Fe/SiO2 Composites on Their Structural and Magnetic Properties.

This research focuses on the production process of soft magnetic composites in the form of 3D bulk compacts made from insulated powder particles using different milling parameters, aiming to enhance their magnetic properties and to study an innovative method of the powder surface "smoothing" technique. A structure analysis using scanning electron microscopy (SEM), EDS, and optical microscopy is also included. We found out that the samples made by the innovative method have lower density values. This can be caused by a more consistent SiO2 insulation layer on highly pure iron powder particles. A correlation between the mechanical smoothing method and better insulation of powder particles can help to provide eco-friendlier solutions for the preparation of soft magnetic composites, such as less usage of reagents and more consistent coverage of powder particles with lower final insulation thickness. The magnetic properties of these compacts are evaluated by coercive field, permeability, and loss measurements. The particle-level smoothing technique in some cases can reduce the value of coercivity up to 20%. For some samples, the ball-to-powder ratio has a bigger impact on magnetic properties than surface treatment, which can be caused by an increased amount of insulation in the SMC compacts.

Hi-PART: Going Beyond Graph Pooling with Hierarchical Partition Tree for Graph-Level Representation Learning

Graph pooling refers to the operation that maps a set of node representations into a compact form for graph-level representation learning. However, existing graph pooling methods are limited by the power of the Weisfeiler–Lehman (WL) test in the performance of graph discrimination. In addition, these methods often suffer from hard adaptability to hyper-parameters and training instability. To address these issues, we propose Hi-PART, a simple yet effective graph neural network (GNN) framework with Hi erarchical Par tition T ree (HPT). In HPT, each layer is a partition of the graph with different levels of granularities that are going toward a finer grain from top to bottom. Such an exquisite structure allows us to quantify the graph structure information contained in HPT with the aid of structural information theory. Algorithmically, by employing GNNs to summarize node features into the graph feature based on HPT’s hierarchical structure, Hi-PART is able to adequately leverage the graph structure information and provably goes beyond the power of the WL test. Due to the separation of HPT optimization from graph representation learning, Hi-PART involves the height of HPT as the only extra hyper-parameter and enjoys higher training stability. Empirical results on graph classification benchmarks validate the superior expressive power and generalization ability of Hi-PART compared with state-of-the-art graph pooling approaches.

Continuous-wave second-harmonic generation in the far-UVC pumped by a blue laser diode

Far-UVC light in the wavelength range of 200–230 nm has attracted renewed interest because of its safety for human exposure and effectiveness in inactivating pathogens. Here we present a compact solid-state far-UVC laser source based on second-harmonic generation (SHG) using a low-cost commercially-available blue laser diode pump. Leveraging the high intensity of light in a nanophotonic waveguide and heterogeneous integration, our approach achieves Cherenkov phase-matching across a bonded interface consisting of a silicon nitride (SiN) waveguide and a beta barium borate (BBO) nonlinear crystal. Through systematic investigations of waveguide dimensions and pump power, we analyze the dependencies of Cherenkov emission angle, conversion efficiency, and output power. Experimental results confirm the feasibility of generating far-UVC, paving the way for mass production in a compact form factor. This solid-state far-UVC laser source shows significant potential for applications in human-safe disinfection, non-line-of-sight free-space communication, and deep-UV Raman spectroscopy.

Mechanical Analysis of Functionally Graded Multilayered Two-Dimensional Decagonal Piezoelectric Quasicrystal Laminates with Imperfect Interfaces

Quasicrystals have a wide range of applications due to their unique multi-field coupling effects and distinctive physical and mechanical characteristics. In this paper, the static and dynamic problems of imperfectly bonded, multilayered, functionally graded, two-dimensional decagonal piezoelectric quasicrystal laminates under mixed boundary conditions are investigated. The state equations in a concise and compact matrix form can be expressed by using differential quadrature regional discrete point expansions in any layer of the laminate. This allows for the representation of displacement, stress, electric potential, and electric displacement components. Then, different imperfect interface conditions are introduced to characterize specific structural and electric contact properties at the bounding interfaces, which are further converted to the interface propagator matrix. Numerical examples are carried out to investigate the impact of varying interface compliances, load types, and functional gradient factors on the static bending and vibration phenomena of QC laminates. These results can be used as references to validate existing or future numerical work on QC laminates and could further guide the design of related QC laminate structures.

Static spherically symmetric solutions in new general relativity

We give a pedagogical introduction to static spherically symmetric solutions in models of New GR, both explaining the basics and showing how all such vacuum solutions can be obtained in elementary functions. In doing so, we coherently introduce the full landscape of these modified teleparallel spacetimes, and find a few special cases. The equations of motion are turned into a very nice and compact form by using the Levi-Civita divergence of the torsion-conjugate; and generalised Bianchi identities are briefly discussed. Another important point we make is that a convenient choice of the radial variable might be instrumental for success of similar studies in other modified gravity models.

Complete Kinematics/Dynamics Modeling and Performance Analysis of a Novel SCARA Parallel Manipulator Based on Screw Theory

Abstract In this paper, a novel Selective Compliance Assembly Robot Arm (SCARA) high-speed parallel manipulator that can realize three-translation and one-rotation motion is proposed, and an accurate dynamic modeling methodology is investigated. The mechanism is composed of four limbs with a double parallelogram structure and a single moving platform. The high bearing capacity and high dynamic response of the novel mechanism make it a viable alternative choice for this kind of automation equipment. The degree-of-freedom (DOF) of the mechanism is analyzed by the screw theory. At the same time, the velocity mapping model of the mechanism is established by the twist screw and the actuated Jacobian matrix. Then, the acceleration mapping model of the mechanism, including the generalized kinematic pairs, is established by reduced acceleration state, the modified Lie screw, and the acceleration Hessian matrix. On this basis, the complete dynamic model with a compact form of the mechanism is deduced by the combination of screw theory and virtual work principle, and the correctness of the developed model is verified by multibody simulation software. Finally, considering the inertial characteristics of the mechanism, the dynamic performance distribution in the reachable workspace of the mechanism is analyzed by the Joint-Reflected Inertia (JRI) index and Coefficient of Variation of joint-space Inertia (CVI) index, and some areas are selected as the task workspace using the above index to guarantee good dynamic performance.

Multiparameter Remote Contact Force Sensor With Embedded Bend Sensing for Tendon-Driven Hand Robots

Integrating multiple sensors without increasing the structural complexity and their original form factor is a major concern in robotic applications, particularly in tendon-driven systems. This study proposes a multiparameter contact force sensor with bend sensing by utilizing an improved Bowden cable design. The proposed sensor consists of an end tip with an elastomer membrane, a Bowden cable consisting of a sheath and dual inner wires, and a remotely separated sensing component. The electrical wirings are decoupled from the mechanical Bowden cable system. The displacement difference between the force-sensing and bend-sensing wires is transmitted through the sheath, indicating the contact force on the end tip. The modeling and experiments verify that the contact force applied on the end tip is linearly related to the sensor output signal and is reliable after repeated measurements. The proposed sensor, utilizing the flexible Bowden cable as its sensing modality, can be integrated into a diverse range of tendon-driven robotic applications. These applications include a robotic hand with tactile and angle sensing capabilities, as well as a soft wearable robot for the hand (Exo-glove Poly II). The compact form factor of the proposed sensor enables geometric sensing without increasing structural complexity for multiparameter sensing in robotic applications.

Design and Validation of Soft Sliding Structure with Adjustable Stiffness for Ankle Sprain Prevention.

This study presents the design and validation of a soft sliding stiffness structure with a soft-rigid layer sliding mechanism. It aims to mitigate ankle sprains and address the progression of chronic ankle instability by providing stiffness support. The soft-rigid layer sliding mechanism of the structure is designed to achieve a wide range of stiffness while maintaining a compact form factor. The structure incorporates rigid retainer pieces within each layer, which allows for sliding within a hollow cuboid structure and enables modulation of stiffness. An analytical model is presented to investigate the variations in stiffness resulting from the different sliding states. The stiffness characteristics of the structure were validated through both bench tests and human subject tests. The gradual sliding of the structure's layer resulted in an increase in stiffness, aligning with the analytical model's predictions. At the most rigid stage (0% alignment), the stiffness exhibited a significant increase of 111.1% compared to the most flexible stage (100% alignment). Additionally, the human subject testing demonstrated a stiffness increase of up to 93.8%. These results underscore the potential applicability of the soft sliding structure in ankle support applications.

Policy instruments as a trigger for urban sprawl deceleration: monitoring the stability and transformations of green areas

The socialist era postponed suburbanisation in Central and Eastern European countries. After 1990, the process became extremely intensive and transformed the compact form of cities into more decentralised and dispersed urban structures. Therefore, the study aims to identify the main trends in land-cover transformation caused by urban sprawl in peri-urban areas of three Central and Eastern European cities (NUTS 3 level: the Pest County, Bratislava Region, and Krakowski subregion). In addition, we identified various policy tools for green infrastructure protection. We further investigated the extent to which the presence of legal means of nature conservation affects the stability of natural and seminatural areas. The research used an original questionnaire and spatio-temporal analysis. It has been confirmed that after decades of socialism, a highly intensive urban sprawl process started in the analysed regions. It generally slowed down after 2000 except for the Krakowski subregion. The majority of new artificial areas replaced agricultural land. Despite the dynamic urban sprawl, almost one-third of the analysed Central and Eastern European peri-urban areas were stable natural and seminatural areas. The traditional nature conservation tools proved to be effective in preserving natural and seminatural areas, but the protection of landscapes exposed to urban sprawl needs specific tools. The effectiveness of urban sprawl control is hindered by the fact that spatial planning competences are dispersed. This research may influence monitoring urban sprawl and offer an innovative method because it combines spatial analysis (quantitative approach) with the impact of policy tools (qualitative approach).

Nanoscale Magnets Embedded in a Microstrip.

Nanoscale magnetic resonance imaging (NanoMRI) is an active area of applied research with potential applications in structural biology and quantum engineering. The success of this technological vision hinges on improving the instrument's sensitivity and functionality. A particular challenge is the optimization of the magnetic field gradient required for spatial encoding and of the radio frequency field used for spin control, in analogy to the components used in clinical MRI. In this work, we present the fabrication and characterization of a magnet-in-microstrip device that yields a compact form factor for both elements. We find that our design leads to a number of advantages, among them a 4-fold increase of the magnetic field gradient compared to those achieved with traditional fabrication methods. Our results can be useful for boosting the efficiency of a variety of different experimental arrangements and detection principles in the field of NanoMRI.

Delosperma buysii (Aizoaceae subfam. Ruschioideae), a new purple-white-flowered vygie species from north-central South Africa

Thus far, six species of Delosperma (Aizoaceae subfam. Ruschioideae) have been recorded from the Gauteng province in north-central South Africa, an essentially summer-rainfall region. Of these, two are purple-flowered, one is purple-white-flowered, while the other species are white- or yellow-flowered. We here describe a further purple-white-flowered species from northwestern Gauteng and adjacent North West province as D. buysii. The new species is contrasted with D. macellum, the only other purple-white-flowered species known from Gauteng. Among other differences, D. buysii has a smaller, more compact growth form in comparison to the larger-growing, often trailing D. macellum, while the sepals of D. buysii are equal in length while those of D. macellum are of two lengths.

Suburban Futures, Density and Amenity: Soft Densification and Incremental Planning for Regeneration

This article explores practical aspects of the compact city agenda as it applies to the ongoing densification of car-dependent suburbs, focusing on Melbourne, Australia. While the idea of compact cities has widespread policy support globally, debate continues regarding the negotiation of compact urban form and its implications for issues like overcrowding, tree canopy, waterways, urban heat, and so forth. Irrespective of the debate, Australian cities are experiencing rapid urban infill, with all areas becoming denser. Some areas of strategic attention afford master planning and planning forethought; however, most of the land in these cities, and at least half of the dwellings being redeveloped, has suburban form, with little or no strategic planning consideration, despite doubling and, in some cases, tripling population density into the future. Significantly, many areas are or will soon achieve population densities that can support vibrant commercial centers, but with little capacity or interest in top-down planning for adding necessary amenities and services. This article shows how, with minimal effort, planning authorities could subtly alter land use planning to allow incremental, but planned, growth of commercial areas, create the destinations the suburbs need to make them vibrant, and deliver less car-dependent local centers.

Morphology changes and the expansion of major port cities in the Philippines from 1990 to 2020

Research concerning urban expansion has been conducted worldwide in the context of global urbanization, yet comprehensive and systematic research on urban growth and morphological changes in Asia is lacking. In this study, the land use, population, and economic development of nine major port cities in the Philippines from 1990 to 2020 were analyzed. The urban land density inverse S function was used to conduct an in-depth analysis of changes in urban spatial morphology. The urban growth patterns were studied by landscape expansion indexes were studied. The results showed that the land area of nine port cities increased by 246.7 km2. Infill expansion in Metro Manila, Cebu, and Bacolod accounted for >60 % of the newly added urban land and has led to a more compact urban form; edge and outlying expansion in General Santos, Batangas, Cagayan de Oro, and Iloilo accounted for >80 % and has led to dynamic changes involving compactness and dispersion. Urban boundaries and terrain limit the development of slow and medium-speed expansion cities; the combination with surrounding cities into megacities can be considered in the future. In contrast, rapidly expanding cities need to improve their compactness and efficiency of urban land use.

A unique SWB multi-slotted four-port highly isolated MIMO antenna loaded with metasurface for IOT applications-based machine learning verification

This study introduces a MIMO antenna system incorporating an epsilon negative Meta Surface (MS). The system’s architects intended for it to have a large usable frequency range, high gain, narrow inter-component spacing, and superior isolation properties with four elements of MIMO antenna that are strategically organized in an orthogonal arrangement and a compact form factor measuring 41 × 41 × 1.6 mm3, utilizing a low-loss Rogers RT5880 substrate. The architecture of the antenna is characterized by integrating a multi-slotted radiating patch, a partial ground plane, and an epsilon-negative Meta Surface. This integration is done by a 7 × 7 Metamaterial array at the back of the MIMO antenna with a dimension of 41 × 41 × 1.6 mm3, resulting in a collective enhancement of the antenna’s overall performance by affecting the phase, amplitude, electromagnetic field and reducing the backward radiation. The separation between the Meta-surface and the MIMO antenna is established at a distance of 6 mm. The antenna’s exceptional super wideband performance is increased from 2–19 GHz to 1.9–20 GHz after using the MS. Moreover, isolation increases from 20 dB to 25.5 dB, Realized gain from 4.5 dBi to 8 dBi, and radiation efficiency from 77% to 89% across the operational bandwidth. The MIMO antenna exhibits remarkable diversity characteristics, as indicated by an envelope correlation coefficient (ECC) of <0.004, a diversity gain (DG) surpassing 9.98 dB, a channel capacity loss (CCL) below 0.3, and a total active reflection coefficient (TARC) measuring 12 dB. Furthermore, a circuit analogous to a resistor–inductor–capacitor (RLC) system is constructed, and four regression methods from the field of machine learning are employed to validate the gain and efficiency achieved. Notably, the linear regression model exhibits exceptional performance, achieving an accuracy of 99%. The MIMO antenna design demonstrates significant potential for many applications in the Internet of Things (IoT), specifically focusing on Vehicle-to-Everything (V2X) communications. These highlight its appropriateness for emerging IoT sectors.

Extrauterine pregnancy in a chihuahua bitch

A four-year-old, 5.3 kg multiparous female Chihuahua bitch was presented to the Obstetrics and Gynaecology Clinic, Faculty of Veterinary Medicine, Hatay Mustafa Kemal University for a routine post-partum genital organ examination one day after parturition. Vital parameters were within the normal ranges. On vaginal examination, there was found no fetal structure in the birth canal. Transabdominal ultrasonography showed no distinct signs of a fetus. However, the radiographic examination detected a round, compact form of fetal skeletal structure in the abdomen. An exploratory laparotomy was decided to remove the fetal structure. Complete haematological and biochemistry analysis illustrated neutrophilia, thrombocytosis, and increased C-reactive protein level. During the surgery, a vascularised mass containing the fetus was removed from the abdomen. As a result of dissection and radiographic examination of the mass, it was determined that it contained a fetus. In conclusion, it was concluded that extrauterine pregnancy in bitches is asymptomatic and may be diagnosed by radiographic examination in the postpartum genital organ examination.

Efficient Amplification of Large‐Signal Spoof Surface Plasmon Polaritons in a Subwavelength Size

AbstractThe advancement of communication systems demands ever‐smaller sizes, leading to the integration of more circuits in compact forms. A promising solution lies in Spoof Surface Plasmon Polaritons (SSPPs), which enable strong confinement, low interference, and a significant wave vector, thereby facilitating smaller sizes. However, the amplification of large plasmonic signals in a compact size remains a daunting scientific challenge for the further development of SSPPs communication systems. In this study, this challenge is tackled by selecting GaN High Electron Mobility Transistors (HEMTs) and load/source‐pull technologies. To ensure efficient operation, impedance‐matching networks are designed, resulting in a remarkably small amplifier structure. The approach involves utilizing the Bayesian optimization (BO) algorithm to fine‐tune the matching network, leading to exceptional amplification performance. The results obtained in the frequency range of 1–3 GHz are highly promising, with both simulated and measured results demonstrating an impressive output power exceeding 40 dBm, a power added efficiency (PAE) surpassing 60%, and a gain exceeding 10 dB. These remarkable achievements underscore the viability of amplifying large‐signal SSPPs and outputting high‐power SSPPs waves within a subwavelength size, opening exciting possibilities for SSPPs communication, sensing, and imaging systems.

A study on δ‐ℐ‐compactness in a mixed fuzzy ideal topological space

Abstract The role of fuzzy 𝛿-open set is highly significant in the study of fuzzy topology initiated by Ganguly and Saha [S. Ganguly and S. Saha, A note on 𝛿-continuity and 𝛿-connected sets in fuzzy set theory, Simon Stevin 62 (1988), 2, 127–141]. This article begins with the introduction of 𝛿-ℐ-open covers in a mixed fuzzy ideal topological space. After that, we introduce 𝛿-ℐ-compactness and then some properties of its are discussed therein. It is shown that the aforesaid compactness is the weaker form of fuzzy compactness. Moreover, we show that if we retopologize the fuzzy topology then in the new environment fuzzy 𝛿-ℐ-compactness and fuzzy compactness are equivalent. In addition, we introduce two different notions of continuity and investigate the behavior between fuzzy 𝛿-ℐ-compactness and fuzzy compactness.

Genetic bases of compact forms among cucurbit crops

The genetic base of compactness has been an area of active research in recent years, with several genes and mutations identified to be associated with the appearance of dwarf phenotypes. Understanding the functions of these genes and the underlying mechanisms of dwarfism in cucurbit crops is essential for developing new cultivars with improved yield and fruit quality. This study presents current data on genes and mutations associated with the evolvement of compact phenotypes in cucurbit crops. The review includes examples of mutant compact phenotypes and their associated genes in representatives of the Cucurbitaceae family, such as Cucurbita maxima Duch., Cucurbita pepo L., Cucurbita moschata Duch., Citrullus lanatus (Thunb.) Matsum. &amp; Nakai, and Cucumis melo L. The review provides up-to-date information on the genetic and molecular bases of compact phenotype formation, as well as molecular markers for detecting known genes associated with reduced plant size.

Improved PVTOL Test Bench for the Study of Over-Actuated Tilt-Rotor Propulsion Systems

In recent years, applications exploiting the advantages of tilt-rotors and other vectored thrust propulsion systems have become widespread, particularly in many novel Vertical Takeoff and Landing (VTOL) configurations. These propulsion systems can provide additional control authority, enabling more complex flight modes, but the resulting control systems can be challenging to design due to the mismatch between the vehicle degrees of freedom and physical input variables. These propulsion systems present both advantages and difficulties because they can exert the same overall forces and moments in many different propulsive configurations. This leads to the traditional non-uniqueness problem when using the inverse dynamics control allocation approach, which is the basis of many popular VTOL control algorithms. In this article, a modified Planar VTOL (PVTOL) test bench configuration, which considers an arbitrary number of co-linear tilting rotors, is introduced as a benchmark for the study of the control allocation problem. The resulting propulsion system is then modeled and linearized in a closed and compact form. This allows a simple and systematic derivation of many of the currently used control allocation approaches. According to the proposed PVTOL configuration, a two-rotor test bench is implemented experimentally and a decoupling control allocation strategy based on Singular Value Decomposition (SVD) analysis is developed. The proposed approach is compared with a traditional input mixer algorithm based on physical intuition. The results show that the SVD-based solution achieves better cross-coupling reduction and preserves the main properties of the physically derived approach. Finally, it is shown that the proposed PVTOL configuration is effective for studying the control allocation problem experimentally in a controlled environment and could serve as a benchmark for comparing different approaches.

Point Cloud Registration for Measuring Shape Dependence of Soft Tissue Deformation by Digital Twins in Head and Neck Surgery

Introduction: A 2½ D point cloud registration method was developed to generate digital twins of different tissue shapes and resection cavities by applying a machine learning (ML) approach. This demonstrates the feasibility of quantifying soft tissue shifts. Methods: An ML model was trained using simulated surface scan data obtained from tumor resections in a pig head cadaver model. It hereby uses 438 2½ D scans of the tissue surface. Tissue shift was induced by a temperature change from 7.91 ± 4.1°C to 36.37 ± 1.28°C. Results: Digital twins were generated from various branched and compact resection cavities (RCs) and cut tissues (CT). A temperature increase induced a tissue shift with a significant volume increase of 6 mL and 2 mL in branched and compact RCs, respectively (p = 0.0443; 0.0157). The volumes of branched and compact CT were decreased by 3 and 4 mL (p < 0.001). In the warm state, RC and CT no longer fit together because of the significant tissue deformation. Although not significant, the compact RC showed a greater tissue deformation of 1 μL than the branched RC with 0.5 μL induced by the temperature change (p = 0.7874). The branched and compact CT forms responded almost equally to changes in temperature (p = 0.1461). Conclusions: The simulation experiment of induced soft tissue deformation using digital twins based on 2½ D point cloud models proved that our method helps to quantify shape-dependent tissue shifts.