Physical Size Research Articles

Optimizing the synthesis of ZnFe2O4 through chemical and physical methods: effects of the synthesis route on the phase purity, inversion, and magnetic properties of spinel zinc ferrite

In this work, ZnFe2O4 ferrites were prepared by chemical (coprecipitation) and ceramic (ball-milling) methods. The effects of the synthesis route on the phase purity, crystallinity, particle size distribution, and magnetic properties were investigated to identify the most appropriate conditions for the synthesis of high-quality ferrites. The samples were examined by x-ray diffraction, scanning electron microscopy, thermal gravimetric analysis, Fourier transform infrared spectroscopy, vibrating sample magnetometry, and Mössbauer spectroscopy. The XRD patterns revealed that a high-purity spinel phase was obtained by coprecipitation at pH ≥ 7 by calcining the pristine powder at T ≥ 900 °C, whereas a single spinel phase was obtained at T ≥ 700 °C in the ball-milling method. The crystallite size of the spinel phase exhibited general increasing trends with the increase of the pH value under the same heat-treatment conditions and with the increase of the calcination temperature. Additionally, the mean physical particle size exhibited an increasing trend with the increase of the calcination temperature. The VSM measurements revealed a noticeable degree of inversion in the spinel ferrites prepared by coprecipitation (exhibiting the highest degree at pH = 10) and an insignificant degree of inversion in the spinel ferrites prepared by the ceramic method. However, calcining the powder exhibiting the highest degree of inversion (prepared by coprecipitation at pH = 10) at 1100 °C resulted in ordering the zinc ions at tetrahedral sites of the spinel structure. Mössbauer spectra for representative zinc ferrite samples prepared by the two methods revealed a major central doublet (with a small magnetic sextet corresponding to the α-Fe2O3 phase in the sample at pH = 7). The hyperfine parameters of the doublet observed in the Mössbauer spectra of the samples, and the corresponding magnetization behavior revealed a higher degree of ionic disorder in the spinel ferrite prepared by coprecipitation.

Identifying the deficiencies of currently available CGM to improve uptake and benefit.

The use of diabetes technologies is increasing worldwide, with health systems facilitating improved access to devices. Continuous glucose monitoring is a complex intervention that provides information on glucose concentration, rate and direction of change, historical data and alerts and alarms for extremes of glucose. These data do not themselves change glycaemia and require translation to a meaningful action for impact. It is, therefore, crucial that such systems advance to better meet the needs of individuals using them. Narrative review of the use of, engagement with, limitations and unmet needs of continuous glucose monitoring systems. CGM devices have made a significant contribution to the self-management of diabetes; however, challenges with access and user experience persist, with multiple limitations to uptake and benefit. These limitations include physical size and implementation, with associated stigma, alarm fatigue, sleep disturbance and the challenge of addressing large volumes of real-time data. Greater personalisation throughout the continuous glucose monitoring journey, with a focus on usability, may improve the benefits derived from the device and reduce the burden of self-management. Healthcare professionals may have unconscious biases that affect the provision of continuous glucose monitors due to deprivation, education, age, ethnicity and other characteristics. Continuous glucose monitoring exerts a dose-dependent response; the more it is used, the more effective it is. For optimal use, continuous glucose monitors must not just reduce the burden of management in one dimension but facilitate net improvement in all domains of self-management for all users.

Perubahan Struktur dan Kondisi Sosial-Ekonomi Masyarakat Pesisir Makassar Pasca Pembangunan Centre Point of Indonesia (CPI)

The development of Center Point Indonesia (CPI) in Makassar City, South Sulawesi has brought significant socio-economic changes to coastal communities. This study investigates changes in the structure and socio-economic situation of Makassar coastal communities with the development of the CPI. The research results show that this development affects the state of the coastal economy, reducing the income of shipping and fishing companies. This change has an impact on the employment situation in coastal areas, which previously was mostly involved in shipping and fishing. Many people are now thinking about looking for another job. The development of CPI has also changed the physical composition and size of coastal communities, which previously were only limited to the sea, are now larger and connected to other areas. This research uses qualitative research methods and collects data from secondary sources such as reports and articles regarding developments in the consumer price index and the situation of coastal communities in Makassar City. The results show that the evolution of the consumer price index has influenced the socio-economic conditions of coastal areas, which previously were mostly involved in shipping and fishing. Many people are now considering looking for another job. This development has also changed the physical composition and size of coastal communities, which were previously only limited to the sea, but are now increasingly spread out and connected to other areas.

Effective orifice diameter: a new sizing parameter of surgical valve prostheses to inform valve selection.

The labeled sizes of surgical valve prostheses and their discordance with the physical internal valve orifice sizes has long been a controversy in the cardiac surgery community, leading many to believe it to be a contributing factor in prosthesis-patient mismatch following valvular replacement surgery. In an attempt to address this issue, the International Organization for Standardization (ISO) 5840-2:2021 standard for surgical valve prostheses recommends that a new sizing parameter, namely, the effective orifice diameter, be provided in labeling by all manufacturers as an indicator of the true flow-passing capacity of a prosthetic valve. The ISO Cardiac Valves Working Group conducted a multi-laboratory round-robin study to investigate whether the effective orifice diameter of a prosthetic surgical valve could be derived repeatably and reproducibly through steady forward-flow testing. A total of seven valve models, each with multiple sizes, were tested, including a mechanical heart valve and multiple biological heart valves. The round-robin study confirmed that the steady forward-flow test had good intra-laboratory repeatability and inter-laboratory reproducibility in deriving the effective orifice diameters of surgical valve prostheses. On average, among the participating laboratories, the experimentally derived effective orifice diameter of a prosthetic heart valve was 3-12 mm smaller than its labeled size. The effective orifice diameter provides better characterization of the hydrodynamic characteristics of a surgical valve prosthesis and can be derived using a validated steady forward-flow test method. This new sizing parameter will soon be adopted by surgical valve manufacturers and provided in device labeling to inform valve selection by surgeons.

Influence of image preprocessing on the segmentation-based reproducibility of radiomic features: in vivo experiments on discretization and resampling parameters

To systematically investigate the impact of image preprocessing parameters on the segmentation-based reproducibility of magnetic resonance imaging (MRI) radiomic features. The MRI scans of 50 patients were included from the multi-institutional Brain Tumor Segmentation 2021 public glioma dataset. Whole tumor volumes were manually segmented by two independent readers, with the participation of eight readers. Radiomic features were extracted from two sequences: T2-weighted (T2) and contrast-enhanced T1-weighted (T1ce). Two methods were considered for discretization: bin count (i.e., relative discretization) and bin width (i.e., absolute discretization). Ten discretization (five for each method) and five resampling parameters were varied while other parameters were fixed. The intraclass correlation coefficient (ICC) was used for reliability analysis based on two commonly used cut-off values (0.75 and 0.90). Image preprocessing parameters had a significant impact on the segmentation-based reproducibility of radiomic features. The bin width method yielded more reproducible features than the bin count method. In discretization experiments using the bin width on both sequences, according to the ICC cut-off values of 0.75 and 0.90, the rate of reproducible features ranged from 70% to 84% and from 35% to 57%, respectively, with an increasing percentage trend as parameter values decreased (from 84 to 5 for T2; 100 to 6 for T1ce). In the resampling experiments, these ranged from 53% to 74% and from 10% to 20%, respectively, with an increasing percentage trend from lower to higher parameter values (physical voxel size; from 1 x 1 x 1 to 2 x 2 x 2 mm3). The segmentation-based reproducibility of radiomic features appears to be substantially influenced by discretization and resampling parameters. Our findings indicate that the bin width method should be used for discretization and lower bin width and higher resampling values should be used to allow more reproducible features.

Varied Attributes of Jalapeño Pepper Cultivars Influence Fresh-cut Product Quality

During the past 40 years, the US fresh-cut product market has experienced a consistent increase in demand because consumers prioritize health and convenience. Increased interest in fresh-cut products and ready-to-eat vegetables has led to innovations in breeding, product selection, and packaging. However, despite the increased popularity of bell pepper and chile pepper (Capsicum annuum L.), research of fresh-cut jalapeño pepper is limited. This study was conducted to identify jalapeño cultivars that could be suitable as a raw fresh-cut product and explore measures beyond tissue membrane electrolyte leakage (EL) of processed products that may be useful for the identification of cultivars suitable for fresh-cut applications. A total of 22 fresh-cut parameters were examined across five cultivars of jalapeño peppers and 10 intercrosses of these cultivars, including visual quality based on an image analysis via a computer vision system, package headspace gas composition, tissue membrane EL, and texture. Based on our results, the genotypes were grouped into five clusters using a cluster analysis. Variables including tissue softening (r2 = 0.95), EL (r2 = 0.95), total energy of the mesocarp (r2 = 0.95), and package headspace carbon dioxide (CO2) partial pressure (r2 = 0.94) had strong associations with the cluster. A principal component analysis with biplots further confirmed the results. Cultivars Goliath and Emerald Fire and their hybrids in the first and second clusters showed good quality for fresh-cut applications. The fifth cluster, represented by a single cultivar, Jalapeño M, had the smallest physical size, rapid shelf-life decline, accumulated CO2 partial pressures, increased EL, and rapid tissue softening in comparison with the other genotypes. All jalapeño cultivars except Jalapeño M maintained good quality until day 14 postprocessing, and some maintained good quality until 21 days postprocessing. Hybrid crosses suggested that two of the cultivars evaluated, Goliath and Emerald Fire, were useful as parents when transferring superior fresh-cut quality traits to progeny. Traditionally, the EL level has been used as an index of freshness (or tissue deterioration). Our results showed that other quality analyses, including measurements of tissue softening via an imaging analysis, and physical analyses of tissue firmness can also be used as indices for the freshness of fresh-cut jalapeños. The results suggest that fruit size, wall thickness, and skin toughness might be useful as predictive measures in the field for the selection of jalapeño genotypes with superior fresh-cut quality.

Parsec-scale cosmic-ray ionisation rate in Orion

Cosmic rays are a key component of the interstellar medium because they regulate the dynamics and chemical processes in the densest and coldest regions of molecular clouds. Still, the cosmic-ray ionisation rate of H$_2$ (crir ) is one of the most debated parameters characterising molecular clouds because of the uncertainties in the adopted chemical networks and analysis techniques. This work aims to homogeneously estimate the crir at parsec scales towards the Orion Molecular Clouds OMC-2 and OMC-3. We explore the change in crir across a whole star-forming region by probing a range of column densities taht has never been explored before. The significant increase in statistics obtained by studying an entire region allows us to place stronger constraints on the range of crir values and exploit its connection with the physical properties of the interstellar medium. The most recent crir estimates are based on o$-$H$_2$D$^+$, which is a direct product of the interaction between cosmic rays and H$_2$ in cold clouds. Since observations of o$-$H$_2$D$^+$ are challenging, we proxy its abundance through CO depletion by employing C18O (2$-$1) observations towards OMC-2 and OMC-3, taking advantage of the existing correlation between the two parameters. Using additional observations of HCO$^+$ (1$-$0) and DCO$^+$ (3$-$2), we determine the deuteration fraction, and we finally derive the map of crir in these two regions. The C18O depletion correlates with both the total column density of H$_2$ and the N$_2$H$^+$ emission across OMC-2 and OMC-3. The obtained depletion factors and deuteration fractions are consistent with previous values obtained in low- and high-mass star-forming regions. These two parameters additionally show a positive correlation in the coldest fields of our maps. We derive cosmic-ray ionisation rates of $ $ s$^ $. These values agree well with previous estimates based on o$-$H$_2$D$^+$ observations. The crir also shows a functional dependence on the column density of H$_2$ across a full order of magnitude ($ $ cm$^ $). The estimated values of crir decrease overall for increasing $N( H_2 $), as predicted by theoretical models. The results delivered by our approach are comparable with theoretical predictions and previous independent studies. This confirms the robustness of the analytical framework and promotes CO depletion as a viable proxy of o$-$H$_2$D$^+$. We also explore the main limitations of the method by varying the physical size of the gas crossed by the cosmic rays (i.e. the path length). By employing a path length obtained from low-resolution observations, we recover values of the crir that are well below any existing theoretical and observational prediction. This discrepancy highlights the need for interferometric observations in order to reliably constrain the crir at parsec scales as well.

Fabrication of nanocrystal forms of ᴅ-cycloserine and their application for transdermal and enteric drug delivery systems.

ᴅ-cycloserine (DCS), an FDA-approved medicine for the treatment of tuberculosis, is also a partial agonist at the glycine recognition site of N-methyl-ᴅ-aspartate (NMDA) receptor and has shown significant treatment efficacy for central nervous system (CNS) disorders including depression, schizophrenia, Alzheimer's disease, and post-traumatic stress disorder. The physicochemical properties of DCS, however, limit the options of formulation and medicinal applications of DCS, and warrants further investigation for the development of CNS therapeutics. Nanocrystals play an important role in pharmaceutic design and development. The properties of nanocrystals are remarkably different from their bulk material counterpart, attributed to the large surface-area-to-volume ratio which can improve the bioavailability. In this study, for the first time, DCS, a highly water-soluble compound, has formed nanocrystals and this was confirmed by scanning electronic microscopy and X-ray powder diffraction. Furthermore, DCS nanocrystals were applied to several formulations to test their stability and then to the in vitro Franz diffusion test with reservoir patch formulation as well as in vivo pharmacokinetics study with enteric capsules. We tested these formulations regarding their nanocrystal physical properties, size effect, and dissolution rate, respectively. We found that DCS nanocrystals showed good performance in the Franz diffusion test and rodent pharmacokinetic studies due to the nanoparticle size and faster dissolution as compared with the commercial DCS powder. These DCS nanocrystal formulations could offer a new approach for the development of an advanced drug delivery system for the treatment of CNS disorders.

A hierarchically normalized physics-informed neural network for solving differential equations: Application for solid mechanics problems

Physics-informed neural networks (PINNs) usually confront significant difficulties to accurately solve partial differential equations (PDEs) due to many pathologies caused by gradient failures during training process. In this paper, a gradient disease regarding the ill-conditioned loss function of the PINN methodology is intensively investigated in both theoretical and experimental aspects. Particularly, the regular PINN approaches can obtain good predictions for trivial problems but may fail to learn solutions when their PDE coefficients and/or physical domain sizes vary. Besides, the influences of neural network structure to the PINN training quality are inferred from the theoretical analyses and also confirmed by relating experiments, in which using large-width multi-layer perceptrons (MLPs) is proved to be beneficial in stabilizing PINN training process. To overcome the abovementioned restrictions, a novel PINN methodology using hierarchically normalized technique (hnPINN) motivated from the developed theory is devised. The key idea of the proposed hnPINN is, on the one hand, to transform the original PDE system into one of two proposed dimensionless forms to alleviate the negative effects of PDE coefficients and domain size; on the other hand, to use secondary output scalers to flexibly calibrate the gradient flow for training effectively and improving the solution preciseness. The determination of the secondary output scaler is formulated by a heuristic framework inspired from theoretical analyses on the hnPINN gradient flow. The obtained results from some typical PDEs and common problems in solid mechanics strongly confirm the high effectiveness of the hnPINN in terms of solution accuracy, superior convergence and performance stability in comparison to those of the vanilla PINN and the non-dimensionalized PINN (ndPINN). As a preprocessing procedure, the hnPINN method is independent on network architectures and also greatly potential to combine with other state-of-the-art PINN models for effectively solving challenged issues in practice.

Impact of changing climate on bryophyte contributions to terrestrial water, carbon, and nitrogen cycles.

Bryophytes, including the lineages of mosses, liverworts, and hornworts, are the second-largest photoautotroph group on Earth. Recent work across terrestrial ecosystems has highlighted how bryophytes retain and control water, fix substantial amounts of carbon (C), and contribute to nitrogen (N) cycles in forests (boreal, temperate, and tropical), tundra, peatlands, grasslands, and deserts. Understanding how changing climate affects bryophyte contributions to global cycles in different ecosystems is of primary importance. However, because of their small physical size, bryophytes have been largely ignored in research on water, C, and N cycles at global scales. Here, we review the literature on how bryophytes influence global biogeochemical cycles, and we highlight that while some aspects of global change represent critical tipping points for survival, bryophytes may also buffer many ecosystems from change due to their capacity for water, C, and N uptake and storage. However, as the thresholds of resistance of bryophytes to temperature and precipitation regime changes are mostly unknown, it is challenging to predict how long this buffering capacity will remain functional. Furthermore, as ecosystems shift their global distribution in response to changing climate, the size of different bryophyte-influenced biomes will change, resulting in shifts in the magnitude of bryophyte impacts on global ecosystem functions.

Understanding off-stoichiometry of Q-phase in Al-Cu-Mg-Si alloys

We perform first-principles density-functional theory (DFT) calculations to resolve the controversy of off-stoichiometry of Q-phase in Al-Cu-Mg-Si system. We compute the single and multiple defect energies (vacancy-vacancy, anti-site–vacancy, anti-site–anti-site) at 0 K and finite temperatures to understand the gap between DFT-predicted lowest energy structure and experimentally observed various stoichiometries of Q-phase. We find that i) the stoichiometry of Al4Cu2Mg8Si7 observed by Arnberg can be explained by the single anti-site defect of Al on Mg site, ii) the stoichiometry of Al5Cu2Mg8Si6 observed by Phragmen can be understood by the multiple anti-site defects of Al on Mg site and Al on Si site, iii) the physical size effect is important in determining the defect formation energetics under a similar chemistry (i.e., composition) of Q-phase. We believe that the proposed defect energetic information and mechanism will be useful to design Q-phase strengthened aluminum alloys based on Integrated Computational Materials Engineering (ICME).

Optimizing shellac nanoparticle fabrication: Influence of formulation and process parameters

This study aimed to fabricate shellac (SHL) nanoparticles by optimizing the formulation and electrospraying process. We investigated the influence of formulation factors, including solvent types and SHL concentration, and process parameters like feed rate and applied voltage, on physical appearance, particle size, size distribution, and aspect ratio. Optimized conditions were determined using a Box–Behnken design. It was found that particle formation was significantly affected by the type of solvent, SHL concentration, applied voltage, and feed rate. Under the optimized conditions, uniform spherical nanoparticles were achieved. Overall, this study presents a simple and effective approach to producing nanoparticles as potential nanocarriers for drugs and related compounds in future applications.

Numerical values modulate size perception.

The link between various codes of magnitude and their interactions has been studied extensively for many years. In the current study, we examined how the physical and numerical magnitudes of digits are mapped into a combined mental representation. In two psychophysical experiments, participants reported the physically larger digit among two digits. In the identical condition, participants compared digits of an identical value (e.g., "2" and "2"); in the different condition, participants compared digits of distinct numerical values (i.e., "2" and "5"). As anticipated, participants overestimated the physical size of a numerically larger digit and underestimated the physical size of a numerically smaller digit. Our results extend the shared-representation account of physical and numerical magnitudes.

Realization of an integrated coherent photonic platform for scalable matrix operations

Optical processing of information holds great promise for addressing many challenges facing the field of computing. However, integrated photonic processors are typically limited by the physical size of the processing units and the energy consumption of high-speed analog-to-digital conversion. In this paper, we demonstrate an integrated, coherent approach to processing temporally multiplexed optical signals using a modular dot-product unit cell to address these challenges. We use these unit cells to demonstrate multiply-accumulate operations on real- and complex-valued inputs using coherent detection and temporal integration. We then extend this to computing the covariance between stochastic bit streams, which can be used to estimate correlation between data streams in the optical domain. Finally, we demonstrate a path to scaling up our platform to enable general matrix-matrix operations. Our approach has the potential to enable highly efficient and scalable optical computing on-chip for a broad variety of AI applications.

Exploring the potential of silymarin-loaded nanovesicles as an effective drug delivery system for cancer therapy: in vivo, in vitro, and in silico experiments.

We aimed to perform a comprehensive study on the development and characterization of silymarin (Syl)-loaded niosomes as potential drug delivery systems. The results demonstrate significant novelty and promising outcomes in terms of morphology, size distribution, encapsulation efficiency, in vitro release behavior, free energy profiles of Syl across the niosome bilayer, hydrogen bonding interactions, antimicrobial properties, cytotoxicity, and in vivo evaluations. The physical appearance, size, and morphology assessment of free niosomes and Syl-loaded niosomes indicated stable and well-formed vesicular structures suitable for drug delivery. Transmission electron microscopy (TEM) analysis revealed spherical shapes with distinct sizes for each formulation, confirming uniform distribution. Dynamic light scattering (DLS) analysis confirmed the size distribution results with higher polydispersity index for Syl-loaded niosomes. The encapsulation efficiency of Syl in the niosomes was remarkable at approximately 91%, ensuring protection and controlled release of the drug. In vitro release studies showed a sustained release profile for Syl-loaded niosomes, enhancing therapeutic efficacy over time. Free energy profiles analysis identified energy barriers hindering Syl permeation through the niosome bilayer, emphasizing challenges in drug delivery system design. Hydrogen bonding interactions between Syl and niosome components contributed to energy barriers, impacting drug permeability. Antimicrobial assessments revealed significant differences in inhibitory effects against S. aureus and E. coli. Cytotoxicity evaluations demonstrated the superior tumor-killing potential of Syl-loaded niosomes compared to free Syl. In vivo studies indicated niosome formulations' safety profiles in terms of liver and kidney parameters compared to bulk Syl, showcasing potential for clinical applications. Overall, this research highlights the promising potential of Syl-loaded niosomes as effective drug delivery systems with enhanced stability, controlled release, and improved therapeutic outcomes.

Auditory Learner

Auditory Learner

Semiphysical Design Concept for Developing Miniaturized Microrobots In Vivo.

The miniaturization of biomedical microrobots is crucial for their in vivo applications. However, it is challenging to reduce their size while maintaining their biomedical functions. To resolve this contradiction, we propose a semiphysical design concept for developing miniaturized microrobots, in which invisible components such as light beams are utilized to replace most of the physical parts of a microrobot, thus minimizing its physical size without sacrificing its biomedical functions. According to this design, we have constructed a semiphysical microrobot (SPM) composed of main light beam, light-responsive microparticle, and auxiliary light beam, serving as the actuation system, recognition part, and surgical claws, respectively. Based on the functions of actuation, biosensing, and microsurgery, a SPM has been applied for a series of applications, including thrombus elimination at the branch vessel, stratified removal of multilayer thrombus, and biosensing-guided microsurgery. The proposed semiphysical design concept should bring new insight into the development of miniaturized biomedical microrobots.

MeerKAT and ALMA view of the AGAL045.804−0.356 clump

Abstract This study presents a detailed analysis of the GAL045.804−0.356 massive star-forming clump. A high-angular resolution and sensitivity observations were conducted using MeerKAT at 1.28 GHz and ALMA interferometer at 1.3 mm. Two distinct centimetre radio continuum emissions (source A and source B) were identified within the clump. A comprehensive investigation was carried out on source A, the G45.804−0.355 star-forming region (SFR) due to its association with Extended Green Object (EGO), 6.7 GHz methanol maser and the spatial coincidence with the peak of the dust continuum emission at 870 μm. The ALMA observations revealed seven dense dust condensations (MM1 to MM7) in source A. The brightest (Sν ∼ 87 mJy) and massive main dense core, MM1, was co-located with the 6.7 GHz methanol maser. Explorations into the kinematics revealed gas motions characterised by a velocity gradient across the MM1 core. Furthermore, molecular line emission showed the presence of an extended arm-like structure, with a physical size of 0.25 pc × 0.18 pc (∼ 50000 au × 30000 au) at a distance of 7.3 kpc. Amongst these arms, two arms were prominently identified in both the dust continuum and some of the molecular lines. A blue-shifted absorption P-Cygni profile was seen in the H2CO line spectrum. The findings of this study are both intriguing and new, utilising data from MeerKAT and ALMA to investigate the characteristics of the AGAL45 clump. The evidence of spiral arms, the compact nature of the EGO and < 2 km s−1 velocity gradient are all indicative of G45.804−0.355 being oriented face-on.

Techno-Economic Analysis of Using Reversible Turbomachinery for Pumped Thermal Energy Storage Systems

Abstract The objective of this paper is to assess the techno-economic performance of different cycle configurations for pumped thermal energy storage (PTES), including the effects of charging electricity costs. Reversible turbomachinery was employed to reduce the capital cost of the system. Brayton cycles with different working fluids and a subcritical Rankine cycle operating with ammonia were compared. Both liquid and packed bed thermal storages were investigated. A new cost correlation for turbomachines, initially established for the turbines of organic Rankine cycles, was developed for compressors and reversible machines. This correlation is based on the number of stages and physical size of the machine, which were estimated considering thermodynamic as well as mechanical limitations. The results indicate that for a plant size of 50 MW and a discharge duration of 8 h, the Brayton system with liquid storage and helium as a working fluid has the lowest levelized cost of storage at 0.138 $/kWh, mainly due to the high thermal conductivity of the fluid. Packed bed thermal energy storage systems were found to be more expensive than liquid storage systems due to the large cost of the pressure vessels, with cost parity reached at a discharge duration of 4 h. However, at this duration, lithium-ion batteries are likely to be cheaper. The results suggest that the levelized cost of storage for the Rankine cycle-based system is slightly higher at 0.151 $/kWh.

A wideband end‐fire stepped slot antenna with gain enhancement and filtering capability

AbstractA wideband end‐fire stepped slot antenna with gain enhancement and filtering capability is proposed. On one hand, a parasitic dipole serving as a director is introduced in the stepped slot to improve the radiation gain of the slot antenna without increasing its physical size. It is found that a gain enhancement of about 2 dB can be achieved after adopting such approach. On the other hand, an absorptive branch possessing a nearly complementary frequency response with regard to the one of the slot antenna is in‐parallel loaded at the microstrip feedline. It allows the partial dissipation of the out‐of‐band/non‐radiated RF‐signal power of the antenna to attain both an RF‐quasi‐absorptive behaviour and filtering capability. It is found that after loading the dissipative branch, the out‐of‐band radiation efficiency of the slot antenna is reduced to less than 20%. The measured results of a fabricated proof‐of‐concept antenna prototype show a reasonable agreement with the simulated ones and verify the RF performance merits of the proposed stepped slot antenna, such as wide RF operating band covering the 3.39−4.73‐GHz range, end‐fire radiation with a front‐to‐back ratio (FBR) above 10 dB, flat radiation gain, and co‐integrated filtering functionality with RF‐quasi‐absorptive capability.