Limited Space Research Articles

Compact planar phased array antenna for extended V2X communication coverage

In this article, a new compact planar phased array antenna is proposed for blind spot reduction in V2X communications. The proposed antenna can be easily integrated on the front-panel or rear-view side by providing 2-dimensional wide communication coverage while overcoming physical integration space limitations. Moreover, because the proposed antenna is based on a planar structure, it can be integrated effectively with beamforming circuits. To verify the proposed antenna, both single and array configurations were fabricated and compared with conventional patch antennas at 5.9 GHz. The proposed single antenna with a size of 1λ0 × 1.1λ0 × 0.02λ0 exhibited a measured bandwidth of 4.3% and a peak gain of 6.1 dBi. The measured HPBWs in the E- and H- planes were approximately 126° and 136°, respectively, compared to 75.5° and 66.9° for the conventional patch antenna. Further, the proposed antenna and reference patch antenna were extended to 1 × 8 array configurations with 8-ch beamforming circuits. The measured scan angle of the proposed antenna was 160°, compared to only 98° for the patch antenna. Finally, a vehicular communication test was conducted with 256-QAM signals, where the proposed 1 × 8 antenna array exhibited a stable error vector magnitude (EVM) over a wide coverage angle of 150°.

Validation of assessments to accurately analyze the body composition of highly trained sitting volleyball players: A pilot study

Body composition is a fundamental component of physical fitness related to the performance of Sitting volleyball (SV) players. Also, establishing the best method for evaluating the body composition of these para-athletes would be highly necessary for this field. The purpose of this study was (1) to describe the body composition of male and female highly trained SV players, (2) to compare the values obtained from this population by two different methods and (3) to establish validity on one of these methods. Thirteen Brazilian SV national team players (five males and eight females) participated in this study. The air-displacement plethysmography (ADP) method as the criterion assessment and the skinfolds (SF) method were conducted for each player. Results showed that there were no significant differences between the values of all players, which ADP and SF measured for body fat percentage (BF%) and body density (BD) (p > 0.05). We found significantly different values between male and female players for BF% by SF (p = 0.04) and BD by SF (p = 0.04). A high degree of reliability was found between ADP and SF measures for BF% and BD. There were statistically significant positive correlations between BF% and BD in all values for both methods (p < 0.01). This pilot study suggests that considering the magnitude of space, expense, and other limitations related to the ADP method against the SF method, we recommend using the SF method, which is a valid, viable and reliable method for measuring body composition in elite SV players.

A Biodegradable Piezoelectric Sensor for Real‐Time Evaluation of the Motor Function Recovery After Nerve Injury

AbstractNerve injury can lead to defects in related motor functions. It is critical to achieve long‐term and convenient real‐time evaluation of motor function recovery status during nerve injury repair. In this study, an implantable PLLA/BTO piezoelectric sensor (PBPS) with good biodegradability and biocompatibility for real time evaluation of the motor function recovery after nerve injury is developed. PLLA fibers doped with BTO are employed as piezoelectric material in PBPS, which can convert the biomechanical signals generated by motion into electrical signals. PBPS can be implant simultaneously with commonly used tissue scaffolds for treatment in the rats with sciatic nerve injury. The linearity of the pressure and the output voltage of PBPS is ≈0.9445. For the evaluation effectiveness, as the treatment process progresses, the signals generated by PBPS exhibited good consistency with EMG signals, indicating effectively evaluation of the motor function. Moreover, the integration of PBPS and wireless module can break the limitations of time and space for sensing and realize wireless evaluation of motor function in rat. The implantable sensor based on PBPS may bring new ideas for the development of implantable bioelectronics.

A digital twin framework for innovating rural ecological landscape control

BackgroundBecause cities prioritize economic development and face ecological space and resource constraints, the development of rural areas, which have untapped potential, should receive increased attention. Consequently, rural ecological landscapes should be constructed through the control of land use types and quality to fully ensure the sustainable development of urban and rural ecosystems. The digital twin is a philosophy and a methodology that connects the digital and physical realms, facilitating realistic and dynamic mapping simulations of the real world. This capability offers valuable insights for digital decision-making, maintenance, and optimization of rural ecological landscapes. Given the digital transformation of rural ecological landscape control, this paper proposes a rural intelligent control approach based on the digital twin concept and new technology.MethodsFive components of the rural ecological landscape digital twin framework are selected to collectively facilitate the monitoring and analysis of rural conditions, formulate strategic solutions, implement management and control behaviors, and enhance participant interaction. The method includes three steps: mapping and fusing information, constructing and managing a database, and constructing a digital platform. Data mining and spatial fusion are performed through targeted mapping methods, and Oracle and ArcGIS SDE are utilized for database construction and fused data management. The twin platform is generated via HTML, desktop application development and geographic information system development technologies using a distributed system as the core.ResultsBased on multiple case studies, our platform efficiently gathers system information on rural ecological landscapes using a twin model. Through evaluation and analysis, it determines landscape governance zones, adjusting them based on land use conditions. The platform refines control schemes with feedback from diverse users, ensuring effective control in various scenarios. Its key advantages include high development efficiency, flexible access, and smooth cross-platform integration. Although implemented in rural China, the proposed digital twin framework is applicable to any rural area requiring ecological landscape digital control.ConclusionsThe value of the platform lies in its powerful information processing capability, overcoming the limitations of time and space and enabling the presentation and integration of fictional scenes Thus, the platform provides a reference for the digital transformation of rural ecological landscape control.

Compression strength of reinforced steel angles

A common reinforcing detail for strengthening open web steel joists is the addition of a rod or plate to an existing angle to form a built-up member. Design standards typically include a limit on the spacing of connections between the components of built-up compression members. The limits are based primarily on more common built-up members such as double angles. Reinforced angles are different than double angles because, among other things, the components are in direct contact limiting potential buckling modes. Prior physical testing is limited; thus, it is unclear if the spacing limits are truly applicable to reinforced angles. The limits can govern the weld spacing for reinforced angles in joists, potentially resulting in more welding than necessary. This experimental and numerical study investigates the compression strength of reinforced angles and how the strength varies with weld spacing. Fifteen reinforced angle specimens were fabricated and tested with variation in reinforcement type, weld spacing, and member effective length. Numerical analyses were performed to expand the range of investigation. Weld spacing had essentially no effect on the experimental strength of the test specimens when the weld spacing was less than or equal to 305 mm (12 in.) on center. Strengths computed per current design provisions were found to be overly conservative. Recommendations to modify the provisions were made. These results lead to a better understanding of the behavior of reinforced angles and enable more efficient reinforcement of open web steel joists.

The northern wheatear is reducing its distribution in its southernmost European range and moving to higher altitudes

Under the current pattern of climate change, mountain bird populations are generally shifting their ranges to higher elevations, tracking their climatic optima. Nevertheless, space limitations at high altitudes constrain mountain species' resilience to climatic change, making them particularly vulnerable. In extreme cases, the climatic niche of some species can move beyond mountaintops, ultimately driving such species to extinction. This study presents the case of the northern wheatear Oenanthe oenanthe in mainland Spain and compares its breeding distribution from 2003 to 2022. Spain, where the species mostly occupies mountain areas, represents its southernmost distribution limit in Europe. We built environmental favourability models using information from the two most recent Spanish bird atlases and a set of climatic, topographic, human activity and lithological variables to determine the factors affecting the occurrence of the species. The influence of climate compared to all other factors was obtained using variation partitioning analysis. The northern wheatear has suffered a strong reduction (67%) in occupied areas and also in favourability throughout mainland Spain (especially in the south) where climate change may have far‐reaching consequences, including local extinctions. Climate explained more than 90% of the variation in the model obtained for 2022. Interestingly, the occupied areas were, on average, 100 m higher in 2022 than in 2003. If the effects of climate warming persist, the northern wheatear will likely disappear in its southernmost distribution limit, being the Sierra de las Nieves National Park population the most vulnerable in mainland Spain. For this reason, it is necessary to implement monitoring programmes for northern wheatear populations, with priority for mountain systems wherein they already occupy higher elevations, as well as further studies on other mountain species.

Sound-Absorbing, Thermal-Insulating Material Based on Poly(methylsiloxane) Xerogel and Cellulose Nanofibers

The automotive industry needs to improve energy efficiency rapidly to achieve carbon neutrality while creating a safe, secure, and comfortable driving environment for customers. Porous sound-absorbing materials and porous thermal insulators are typically used to satisfy these requirements despite limitations in mass and space. While these porous materials are similar, the microstructures they offer for high performance differ in the size and connectivity of their fluid phases, which enhances the difficulty of achieving excellent sound absorption and thermal insulation in the same material. In this study, a hydrophobic cellulose nanofiber–poly(methylsiloxane) xerogel composite was developed using computational microstructure modeling. This porous material has high porosity and excellent thermal insulation and sound absorption properties.

Low-Frequency Sound Absorption Potential of Subwavelength Absorbers Based on Coupled Micro-Slit Panels

Due to space limitations during installation, reducing low-frequency noise has always been a challenging area. Sub-wavelength structures are typically favored in such scenarios for noise reduction. This paper explores the potential of micro-slit panels (MSP) for low-frequency sound absorption. To further optimize the panel thickness, coupled MSPs (CMSP) with a distance between two MSPs of less than 1 mm are proposed. Firstly, the low-frequency absorption performances of a single MSP based on two optimized schemes – the cavity-depth optimal scheme (COS) and the panel thickness optimal scheme (TOS) – are examined and compared with those of existing ultrathin metamaterials. The results demonstrate that MSP has significant potential for low frequency sound absorption, and COS allows for a smaller overall structural thickness but a larger panel thickness than TOS. Secondly, to reduce the panel thickness, the CMSP is developed and the theoretical model of its acoustic impedance is established and validated by experiments. Then, based on the theoretical model, the low-frequency absorption potential of CMSP is optimized using COS. The results show that both the overall thickness and the panel thickness of the CMSP absorber are reduced while maintaining better performance. Furthermore, the proposed absorber achieves a subwavelength scale since its total thickness can be as small as 0.138λ.

Exploration and Practice of Online and Offline Hybrid Teaching Mode in Equipment Training

Traditional equipment practical training teaching mainly focuses on group practical operation, and there is a problem of physical space limitation. This paper takes the practical training teaching method as the research object, designs the online and offline hybrid teaching mode of equipment practical training courses, relies on the "1+N" new practical training teaching platform and the high-quality resources of military-civilian integration, takes "teaching + learning + examination + evaluation" as the main line, and realizes the optimization of practical training content, the integration of curriculum ideology and politics, and the innovation of teaching methods. Through the comprehensive transformation of such courses, it further stimulates students' enthusiasm for loving and protecting equipment, integrating learning and thinking, and comprehensively improves students' job competence and the teaching quality of equipment practical training courses.

The hidden Lorentz covariance of quantum mechanics

This paper introduces a systematic algorithm for deriving a new unitary representation of the Lorentz algebra (so(1,3)) and an irreducible unitary representation of the extended (anti) de-Sitter algebra (so(2,4)) on L2(R3,1r). This representation is equivalent to a representation on L2(R3), and the corresponding similarity transformation is identified. An explicit representation in terms of differential operators is given, and it is shown that the inner product is Lorentz invariant. Ensuring Lorentz covariance demands a modification of the Heisenberg algebra, recognized as a phase space algebra at the interface of gravitational and quantum realms (IGQR), which we consider subordinate to Lorentz covariance. It is also demonstrated that time evolution can be cast in a manifestly covariant form. Each mass sector of the Hilbert space carries a representation of the Lorentz algebra, and the (anti) de-Sitter algebra on each mass sector contracts to the Poincare algebra in the flat configuration and momentum space limits. Finally, we show that three-dimensional fuzzy space also carries a unitary representation of these algebras, algebraically equivalent to the L2(R3,1r) representation but not necessarily equivalent as representations. Several outstanding issues are identified for future exploration.

Gopakumar-Vafa invariants and the Emergent String Conjecture

The Emergent String Conjecture of Lee, Lerche, and Weigand holds that every infinite-distance limit in the moduli space of a quantum gravity represents either a decompactification limit or an emergent string limit in some duality frame. Within the context of 5d supergravities coming from M-theory compactifications on Calabi-Yau threefolds, we find evidence for this conjecture by studying (a) the gauge couplings and (b) the BPS spectrum, which is encoded in the Gopakumar-Vafa invariants of the threefold. In the process, we disuss a testable geometric consequence of the Emergent String Conjecture, and we verify that it is satisfied in all complete intersection Calabi-Yau threefolds in products of projective spaces (CICYs).

Determining Exact Quantiles with Randomized Summaries

Quantiles are fundamental statistics in various data science tasks, but costly to compute, e.g., by loading the entire data in memory for ranking. With limited memory space, prevalent in end devices or databases with heavy loads, it needs to scan the data in multiple passes. The idea is to gradually shrink the range of the queried quantile till it is small enough to fit in memory for ranking the result. Existing methods use deterministic sketches to determine the exact range of quantile, known as deterministic filter, which could be inefficient in range shrinking. In this study, we propose to shrink the ranges more aggressively, using randomized summaries such as KLL sketch. That is, with a high probability the quantile lies in a smaller range, namely probabilistic filter, determined by the randomized sketch. Specifically, we estimate the expected passes for determining the exact quantiles with probabilistic filters, and select a proper probability that can minimize the expected passes. Analyses show that our exact quantile determination method can terminate in P passes with 1-δ confidence, storing O(N 1/P logP-1/2P (1/δ)) items, close to the lower bound Ømega(N1/P) for a fixed δ. The approach has been deployed as a function in an LSM-tree based time-series database Apache IoTDB. Remarkably, the randomized sketches can be pre-computed for the immutable SSTables in LSM-tree. Moreover, multiple quantile queries could share the data passes for probabilistic filters in range estimation. Extensive experiments on real and synthetic datasets demonstrate the superiority of our proposal compared to the existing methods with deterministic filters. On average, our method takes 0.48 fewer passes and 18% of the time compared with the state-of-the-art deterministic sketch (GK sketch).

An Updated Review on Probiotic Production and Applications

Microorganisms are ubiquitous and have been exploited for centuries to generate primary and secondary metabolites essential for human welfare and environmental sustainability. Microorganisms occupy a prominent position in the industrial sector due to their unique properties, such as the limited time and space required for their growth and proliferation, as well as their easy manipulation of the genetic material. Among all the microorganisms, probiotics have grabbed the attention of researchers because of their nonpathogenic nature and immersive application in treating digestive ailments and vitamin deficiency, boosting immunity, and detoxifying harmful chemicals. Furthermore, probiotics are widely used to treat various diseases such as constipation, colon cancer, type 2 diabetes mellitus, and obesity, as well as a range of intestinal disorders, including inflammatory bowel disease, among others. The updated information on these diseases and the role of probiotics has not been updated in the past few years. The present review covers updated information on the role of probiotics in these topics. The growth of populations around the globe has attracted the attention of scientists, primarily investigating diverse technologies to meet the gap between probiotic production and demand. With the support of standardized tools and techniques, researchers have explored the potent probiotic strains feasible for industrial production and treating health ailments. In the current review, we have curated the potential information essential for the screening, strain selection, production, and application necessary for probiotic researchers.

Optimizing the Economic Order Quantity Using Fuzzy Theory and Machine Learning Applied to a Pharmaceutical Framework

In this article, we present a novel methodology for inventory management in the pharmaceutical industry, considering the nature of its supply chain. Traditional inventory models often fail to capture the particularities of the pharmaceutical sector, characterized by limited storage space, product degradation, and trade credits. To address these particularities, using fuzzy logic, we propose models that are adaptable to real-world scenarios. The proposed models are designed to reduce total costs for both vendors and clients, a gap not explored in the existing literature. Our methodology employs pentagonal fuzzy number (PFN) arithmetic and Kuhn–Tucker optimization. Additionally, the integration of the naive Bayes (NB) classifier and the use of the Weka artificial intelligence suite increase the effectiveness of our model in complex decision-making environments. A key finding is the high classification accuracy of the model, with the NB classifier correctly categorizing approximately 95.9% of the scenarios, indicating an operational efficiency. This finding is complemented by the model capability to determine the optimal production quantity, considering cost factors related to manufacturing and transportation, which is essential in minimizing overall inventory costs. Our methodology, based on machine learning and fuzzy logic, enhances the inventory management in dynamic sectors like the pharmaceutical industry. While our focus is on a single-product scenario between suppliers and buyers, future research hopes to extend this focus to wider contexts, as epidemic conditions and other applications.

Density affects rearing performance of juvenile landlocked fall Chinook Salmon

AbstractObjectiveDensity‐related information for landlocked fall Chinook Salmon Oncorhynchus tshawytscha shortly after first feeding is poorly understood. This study was undertaken to determine the effects of a range of rearing densities (low, intermediate, and high) on rearing performance and survival of newly feed‐trained juvenile landlocked fall Chinook Salmon.MethodsThe fish were reared for 66 days in 1.8‐m (diameter) tanks with approximate volume of 2036 L at one of three loadings of approximately 2500, 5000, or 10,000 fish/tank.ResultThe initial and final densities for each of the three loadings were 0.73 and 8.93, 1.45 and 16.41, and 2.90 and 26.86 kg/m3, respectively. At the end of the study, the specific growth rates were significantly lower, total lengths were significantly shorter, and feed conversion ratios were significantly greater in the fish from the highest‐density treatment relative to the fish in the other treatments. Percentage of weight gain, final weights, and condition factor were significantly reduced in fish from the highest‐density treatment relative those at the lowest density. There were no significant differences in any growth metrics between fish that were reared at the lowest and intermediate densities. The intermediate density (5000 fish/tank) produced intermediate results that did not significantly differ from either the highest or lowest densities. Mortality was not significantly different among the density treatments.ConclusionAn initial loading of 5000 fish in 1.8‐m (diameter) circular tanks, corresponding to initial and final densities of 1.45 and 16.41 kg/m3, respectively, is recommended to minimize the detrimental effects of density on newly feeding Chinook Salmon while maximizing their production in often limited hatchery space.

New Aspect of Chiral SU(2) and U(1) Axial Breaking in QCD

The violation of the U(1) axial symmetry in QCD is stricter than the chiral SU(2) breaking simply because of the presence of the quantum axial anomaly. If the QCD gauge coupling is sent to zero (the asymptotic free limit, where the U(1) axial anomaly does not exist), the strength of the U(1) axial breaking coincides with that of the chiral SU(2) breaking, which we, in short, call an axial–chiral coincidence. This coincidence is trivial since QCD then becomes a non-interacting theory. Actually, there exists another limit in the QCD parameter space, where an axial–chiral coincidence occurs even with nonzero QCD gauge coupling, which can be dubbed a nontrivial coincidence: it is the case with the massive light quarks (ml≠0) and the massless strange quark (ms=0) due to the flavor-singlet nature of the topological susceptibility. This coincidence is robust and tied to the anomalous chiral Ward–Takahashi identity, which is operative even at hot QCD. This implies that the chiral SU(2) symmetry is restored simultaneously with the U(1) axial symmetry at high temperatures. This simultaneous restoration is independent of ml(≠0) and, hence, is irrespective of the order of the chiral phase transition. In this paper, we discuss how the real-life QCD can be evolved from the nontrivial chiral–axial coincidence limit by working on a Nambu–Jona–Lasinio model with the U(1) axial anomaly contribution properly incorporated. It is shown that, at high temperatures, the large differences between the restorations of the chiral SU(2) symmetry and the U(1) axial symmetry for two light quarks and a sufficiently large current mass for the strange quark are induced by a significant interference of the topological susceptibility. Thus, the deviation from the nontrivial coincidence, which is monitored by the strange quark mass controlling the topological susceptibility, provides a new way of understanding the chiral SU(2) and U(1) axial breaking in QCD.

OVERVIEW OF THE COMFORT ASPECT OF MEDICAL RECORD STORAGE ROOM AT KRAMATWATU PUSKESMAS

Background : The security of the medical record file storage room is one of the main parts to support the security of the medical record file, besides that there are still many health care facilities that underestimate the security of the medical record file storage room, look down on the eyes, and consider trivial things for the security of the record file storage room. medical records in addition to the security of the medical record file itself. The purpose of this study was to find out the review of the Security Aspects of the Medical Record File Storage Room at the Kramatwatu Health Center, South Tangerang. This research uses descriptive research method. From the results of observations and interviews, it was found that the SOP regarding the security of the medical record storage room was already available, but in its application it was still not optimal due to space limitations, the available storage space is not 100% in accordance with the criteria. The cleanliness aspect of the medical record file storage room is not fully appropriate, there is no fixed schedule for cleaning the medical record room, and the APAR is not yet available specifically in themedical record storage room. The conclusion of this study is that there is no SOP for work instructions and the safety of the medical record file storage room, the storage space in the Puskesmas has not been able to accommodate the available medical record files. APAR is not yet available specifically in the medical record storage room. The conclusion of this study is that there is no SOP for work instructions and the safety of the medical record file storage room, the storage space in the Puskesmas has not been able to accommodate the available medical record files. APAR is not yet available specifically in the medical record storage room. The conclusion of this study is that there is no SOP for work instructions and the safety of the medical record file storage room, the storage space in the Puskesmas has not been able to accommodate the available medical record files. APAR is not yet available specifically in the medical record storage room.

Thermal Design of Stacked Power Modules for Electric Drive Applications

This paper reports the thermal design of a stacked arrangement inserting four IGBT modules between five heat sinks to achieve good cooling performance while enabling them to be installed into the limited space. Such stacked four IGBT modules can be used for a variable voltage converter (VVC), a three-phase motor inverter (M-INV) and a three-phase generator inverter (G-INV) of one electric control system in one electric vehicle or hybrid electric vehicle. Work presented in this paper are the thermally related structure design and thermalelectric and computational fluid dynamics coupled simulation, while the prototyping and thermal test of the stacked arrangement are still ongoing. The simulation results indicate that the stacked arrangement can be designed into a compact 121 mm × 94.7 mm × 90.8 mm structure while achieving the maximum virtual junction temperature below 150°C under the coolant feed temperature of 70°C, flow rate of 10 L/min and pressure drop of 0.16 bar for the VVC delivering 150 kW, the M-INV delivering 100 kW and the G-INV delivering 50 kW. If validated with the ongoing work, the stacked arrangement can be employed to increase power density and improve electrical and thermal performance of the power modules in the electric control systems with multiple converters/inverters.

Exploring the barriers to mental health service utilization in the Bolgatanga Municipality: the perspectives of family caregivers, service providers, and mental health administrators

BackgroundMental health service utilization remains a challenge in developing countries, with numerous barriers affecting access to care. Albeit data suggest poor utilization of mental health services in the Bolgatanga Municipality in Ghana, no studies have explored the barriers to the utilization of mental health services. Therefore, this study explored the perspectives of family caregivers, service providers, and mental health service administrators on the barriers to mental health service utilization in the Bolgatanga Municipality, Ghana.MethodsA qualitative descriptive design was employed for the study. Nineteen participants were purposively sampled from two hospitals including fifteen family caregivers, two service providers, and two mental health administrators. Data were collected through individual in-depth interviews using a semi-structured interview guide. Audio-recorded interviews were transcribed verbatim and thematically analyzed using NVivo 12 pro software.ResultsFive main themes emerged including individual-level barriers, interpersonal barriers, community-level barriers, organizational-level barriers, and policy-level barriers. At the individual level, lack of insight, poor treatment compliance, and financial challenges were prominent barriers. Interpersonal barriers included family pressure influenced by cultural and spiritual beliefs. At the community level, stigma and mental health illiteracy were identified as significant barriers. At the organizational level, barriers encompassed inadequate staffing, limited space, and staff attitudes. Policy-level barriers included the neglect of mental health in policies and the non-inclusion of mental health services in the National Health Insurance Scheme.ConclusionThis study highlights the complexity of barriers to mental health service utilization and underscores the need for a comprehensive approach to address them. Collaborative efforts involving healthcare providers, policymakers, communities, and families are essential to mitigate these barriers. It is imperative to consider these barriers when developing strategies to improve the utilization of mental health services in Ghana.

Reimagining Urban Spaces: Green Spaces, Obesity, and Health Resilience in an Era of Extreme Heat.

Record-breaking heat waves intensified by climate change pose both environmental and health threats, necessitating a balance between urban sustainability and well-being. Extreme heat and limited green space access are drivers of obesity prevalence, with decreased proximity to green spaces correlating with higher rates of obesity in nearby communities. In contrast, access to such green spaces fosters physical activity, well-being, and community cohesion, especially crucial in marginalized communities facing health disparities due to historical policies like redlining and underinvestment in social gathering spaces. Despite challenges, green space investment offers healthcare savings and environmental gains, necessitating a shift in perception towards viewing green spaces as essential for urban living. As heat waves persist, integrating health and sustainability in urban planning is paramount. Health and medical communities must play an active role in advocating for equitable access to urban green spaces, as they possess influential positions to address climate-related health disparities through localized advocacy.