bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigating the Dynamic Mechanical Properties and Strengthening Mechanisms of Ti-6Al-4V Alloy by Using the Ultrasonic Surface Rolling Process
Authors: Zha Xuming , Yuan Zhi , Qin Hao , Xi Linqing , Guo Yunwu , Xu Zhilong , Dai Xing , Jiang Feng
Published: March 2024

The demand for titanium alloy has been increasing in various industries, including aerospace, marine, and biomedical fields, as they fulfilled the need for lightweight, high-strength, and corrosion-resistant material for modern manufacturing. However, titanium alloy has relatively low hardness, poor wear performance, and fatigue properties, which limits its popularization and application. These disadvantages could be efficiently overcome by surface strengthening technology, such as the ultrasonic surface rolling process (USRP). In this study, the true thermo-mechanical deformation behavior of Ti-6Al-4V was obtained by dynamic mechanical experiment using a Hopkinson pressure bar. Moreover, USRP was applied on the Ti-6Al-4V workpiece with different parameters of static forces to investigate the evolution in surface morphology, surface roughness, microstructure, hardness, residual stress, and fatigue performance. The strain rate and temperature during the USRP of Ti-6Al-4V under the corresponding conditions were about 3000 s−1 and 200 °C, respectively, which were derived from the numerical simulation. The correlation between the true thermo-mechanical behavior of Ti-6Al-4V alloy and the USRP parameters of the Ti-6Al-4V workpiece was established, which could provide a theoretical contribution to the optimization of the USRP parameters. After USRP, the cross-sectional hardness distribution of the workpiece was shown to initially rise, followed by a subsequent decrease, ultimately to matrix hardness. The cross-sectional residual compressive stress distribution of the workpiece showed a tendency to initially reduce, then increase, and finally decrease to zero. The fatigue performance of the workpiece was greatly enhanced after USRP due to the effect of grain refinement, work hardening, and beneficial residual compressive stress, thereby inhibiting the propagation of the fatigue crack. However, it could be noted that the excessive static force parameter of USRP could induce the decline in surface finish and compressive residual stress of the workpiece, which eliminated the beneficial effect of the USRP treatment. This indicated that the choice of the optimal USRP parameters was highly crucial. This work would be conducive to achieving high-efficiency and low-damage USRP machining, which could be used to effectively guide the development of high-end equipment manufacturing.
Shot Peening Effect on Sliding Wear in 0.9% NaCl of Additively Manufactured 17-4PH Steel
Authors: Walczak Mariusz , Świetlicki Aleksander , Szala Mirosław , Turek Marcin , Chocyk Dariusz
Published: March 2024

The growing demand for modern steels showing corrosion and tribological resistance has led to their increased use in the production of medical devices. This study analyzed the effect of shot peening on wear resistance in 0.9% NaCl solution of 17-4PH steel produced by direct laser metal sintering (DMLS) technology. The study’s novelty relies on revealing the effect of shot peening (SP) surface treatment on the wet sliding wear resistance of 17-4PH steel produced with DMLS. Moreover, in the context of 17-4PH steel application for medical devices, the 0.9% NaCl tribological environment were selected, and SP processes were conducted using steel CrNi shot and ceramic (ZrO2) beads. The up-to-date scientific literature has not identified these gaps in the research. DMLS technology makes it possible to obtain products with complex architectures, but it also faces various challenges, including imperfections in the surface layer of products due to the use of 3D printing technology itself. The chemical and phase composition of the materials obtained, Vickers hardness, surface roughness, and microscopic and SEM imaging were investigated. Tribological tests were carried out using the ball-on-disc method, and the surfaces that showed traces of abrasion to identify wear mechanisms were subjected to SEM analysis. The XRD phase analysis indicates that austenite and martensite were found in the post-production state, while a higher martensitic phase content was found in peened samples due to phase transformations. The surface hardness of the peened samples increased by more than double, and the post-treatment roughness increased by 12.8% after peening CrNi steels and decreased by 7.8% after peening ZrO2 relative to the reference surfaces. Roughness has an identifiable effect on sliding wear resistance. Higher roughness promotes material loss. After the SP process, the coefficient of friction increased by 15.5% and 20.7%, while the wear factor (K) decreased by 25.9% and 32.7% for the samples peened with CrNi steels and ZrO2, respectively. Abrasive and adhesive mechanisms were dominant, featured with slight fatigue. The investigation showed a positive effect of SP on the tribological properties of DMSL 17-4PH.
SERS Performance of Ti3C2Tx MXene-Based Substrates Correlates with Surface Morphology
Authors: Salehtash Farnoush , Annušová Adriana , Stepura Anastasiia , Soyka Yaryna , Halahovets Yuriy , Hofbauerová Monika , Mičušík Matej , Kotlár Mário , Nádaždy Peter , Albrycht Paweł , Šiffalovič Peter , Jergel Matej , Omastová Mária , Majková Eva
Published: March 2024

The surface-enhanced Raman scattering (SERS) properties of low-dimensional semiconducting MXene nanoflakes have been investigated over the last decade. Despite this fact, the relationship between the surface characteristics and SERSing performance of a MXene layer has yet to be comprehensively investigated and elucidated. This work shows the importance of surface morphology on the overall SERS effect by studying few-layer Ti3C2Tx MXene-based SERS substrates fabricated by vacuum-assisted filtration (VAF) and spray coating on filter paper. The VAF deposition results in a dense MXene layer suitable for SERS with high spot-to-spot and substrate-to-substrate reproducibility, with a significant limit of detection (LoD) of 20 nM for Rhodamine B analyte. The spray-coated MXenes film revealed lower uniformity, with a LoD of 50 nM for drop-casted analytes. Moreover, we concluded that the distribution of the analyte deposited onto the MXene layer is affected by the presence of MXene aggregates created during the deposition of the MXene layer. Accumulation of the analyte molecules in the vicinity of MXene aggregates was observed for drop-casted deposition of the analyte, which affects the resulting SERS enhancement. Ti3C2Tx MXene layers deposited on filter paper by VAF offer great potential as a cost-effective, easy-to-manufacture, yet robust, platform for sensing applications.
Finite Element Simulation and Microstructural Evolution Investigation in Hot Stamping Process of Ti6Al4V Alloy Sheets
Authors: Qu Mingjia , Gu Zhengwei , Li Xin , Wang Jianbo , Yu Ge , Yi Lingling
Published: March 2024

Titanium alloy hot stamping technology has a wide range of application prospects in the field of titanium alloy part processing due to its high production efficiency and low manufacturing cost. However, the challenges of forming titanium alloy parts with large depths and deformations have restricted its development. In this study, the hot stamping process of a Ti6Al4V alloy box-shaped part was investigated using ABAQUS 2020 software. The thermodynamic properties of a Ti6Al4V alloy sheet were explored at different temperatures (400 °C, 500 °C, 600 °C, 700 °C, 800 °C) and different strain rates (0.1 s−1, 0.05 s−1, 0.01 s−1). In addition, the influence law of hot stamping process parameters on the minimum thickness of the formed part was revealed through the analysis of response surface methodology (RSM), ultimately obtaining the optimal combination of process parameters for Ti6Al4V alloy hot stamping. The experimental results of the hot stamping process exhibited a favorable correlation with the simulated outcomes, confirming the accuracy of the numerical simulation. The study on the microstructure evolution of the formed parts showed that grain refinement strengthening occurred in the part with large deformation, and the formed box-shaped parts exhibited a uniform and fine microstructure overall, demonstrating high forming quality. The achievements of the work provide important guidance for the fabrication of titanium alloy parts with large depths and deformations used in heavy industrial production.
A Study on the Nature of Complexity in the Spanish Electricity Market Using a Comprehensive Methodological Framework
Authors: Inglada-Pérez Lucía , Gil Sandra González y
Published: March 2024

The existence of chaos is particularly relevant, as the identification of a chaotic behavior in a time series could lead to reliable short-term forecasting. This paper evaluates the existence of nonlinearity and chaos in the underlying process of the spot prices of the Spanish electricity market. To this end, we used daily data spanning from 1 January 2013, to 31 March 2021 and we applied a comprehensive framework that encompassed a wide range of techniques. Nonlinearity was analyzed using the BDS method, while the existence of a chaotic structure was studied through Lyapunov exponents, recurrence plots, and quantitative recurrence analysis. While nonlinearity was detected in the underlying process, conclusive evidence supporting chaos was not found. In addition, the generalized autoregressive conditional heteroscedastic (GARCH) model accounts for part of the nonlinear structure that is unveiled in the electricity market. These findings hold substantial value for electricity market forecasters, traders, producers, and market regulators.
Study on the Anti-Mycobacterium marinum Activity of a Series of Marine-Derived 14-Membered Resorcylic Acid Lactone Derivatives
Authors: Jing Qian-Qian , Yin Jun-Na , Cheng Ya-Jie , Zhang Qun , Cao Xi-Zhen , Xu Wei-Feng , Shao Chang-Lun , Wei Mei-Yan
Published: March 2024

With the emergence of drug-resistant strains, the treatment of tuberculosis (TB) is becoming more difficult and there is an urgent need to find new anti-TB drugs. Mycobacterium marinum, as a model organism of Mycobacterium tuberculosis, can be used for the rapid and efficient screening of bioactive compounds. The 14-membered resorcylic acid lactones (RALs) have a wide range of bioactivities such as antibacterial, antifouling and antimalarial activity. In order to further study their bioactivities, we initially constructed a 14-membered RALs library, which contains 16 new derivatives. The anti-M. marinum activity was evaluated in vitro. Derivatives 12, 19, 20 and 22 exhibited promising activity with MIC90 values of 80, 90, 80 and 80 μM, respectively. The preliminary structure–activity relationships showed that the presence of a chlorine atom at C-5 was a key factor to improve activity. Further studies showed that 12 markedly inhibited the survival of M. marinum and significantly reduced the dosage of positive drugs isoniazid and rifampicin when combined with them. These results suggest that 12 is a bioactive compound capable of enhancing the potency of existing positive drugs, and its effective properties make it a very useful leads for future drug development in combating TB resistance.
Geometry Scaling for Externally Balanced Cascade Deterministic Lateral Displacement Microfluidic Separation of Multi-Size Particles
Authors: Yin Heyu , Dávila-Montero Sylmarie , Mason Andrew J.
Published: March 2024

To non-invasively monitor personal biological and environmental samples in Internet of Things (IoT)-based wearable microfluidic sensing applications, the particle size could be key to sensing, which emphasizes the need for particle size fractionation. Deterministic lateral displacement (DLD) is a microfluidic structure that has shown great potential for the size fractionation of micro- and nano-sized particles. This paper introduces a new externally balanced multi-section cascade DLD approach with a section-scaling technique aimed at expanding the dynamic range of particle size separation. To analyze the design tradeoffs of this new approach, a robust model that also accounts for practical fabrication limits is presented, enabling designers to visualize compromises between the overall device size and the achievement of various performance goals. Furthermore, results show that a wide variety of size fractionation ranges and size separation resolutions can be achieved by cascading multiple sections of an increasingly smaller gap size and critical separation dimension. Model results based on DLD theoretical equations are first presented, followed by model results that apply the scaling restrictions associated with the second order of effects, including practical fabrication limits, the gap/pillar size ratio, and pillar shape.
Design of High-Gain Antenna Arrays for Terahertz Applications
Authors: Ji Xinran , Chen Yu , Li Jing , Wang Dian , Zhao Yue , Wu Qiannan , Li Mengwei
Published: March 2024

A terahertz band (0.1–10 THz) has the characteristics of rich spectrum resources, high transmission speed, strong penetration, and clear directionality. However, the terahertz signal will suffer serious attenuation and absorption during transmission. Therefore, a terahertz antenna with high gain, high efficiency, and wide bandwidth is an indispensable key component of terahertz wireless systems and has become a research hotspot in the field of antennas. In this paper, a high-gain broadband antenna is presented for terahertz applications. The antenna is a three-layer structure, fed by a grounded coplanar waveguide (GCPW), using polytetrafluoroethylene (PTFE) material as the dielectric substrate, and the metal through-hole of the dielectric substrate forms a substrate-integrated waveguide (SIW) structure. The metal fence structure is introduced to reduce the coupling effect between the radiation patches and increase the radiation bandwidth and gain. The center frequency is 0.6366 THz, the operating bandwidth is 0.61–0.68 THz, the minimum value of the voltage standing wave ratio (VSWR) is 1.00158, and the peak gain is 13.14 dBi. In addition, the performance of the designed antenna with a different isolation structure, the length of the connection line, the height of the substrate, the radius of the through-hole, and the thickness of the patch is also studied.
Efficacy and Tolerability of a Scutellaria lateriflora L. and Cistus × incanus L.-Based Chewing Gum on the Symptoms of Gingivitis: A Monocentric, Randomized, Double-Blind, Placebo-Controlled Clinical Trial
Authors: Di Minno Alessandro , Ullah Hammad , De Lellis Lorenza Francesca , Buccato Daniele Giuseppe , Baldi Alessandra , Cuomo Paola , El-Seedi Hesham R. , Khalifa Shaden A. M. , Xiao Xiang , Piccinocchi Roberto , Piccinocchi Gaetano , Sacchi Roberto , Daglia Maria
Published: March 2024

Preclinical studies have shown that the combination of Cistus × incanus L. and Scutellaria lateriflora L. extracts exerts beneficial effects on oral health against gingivitis. Thus, this study aimed to assess the tolerability of a chewing gum and its efficacy on gingivitis in a double-blind, placebo-controlled clinical trial. Enrolled subjects (n = 60, 18–70 years) were randomized to receive two chewing gums or a placebo daily for 3 months. At baseline (t0) and monthly (t1, t2, and t3) timepoints, the Quantitative Gingival Bleeding Index (QGBI), the Modified Gingival Index (MGI), and the Oral Health 15 items (OH-15)] were employed to assess potential improvements in gingivitis. Pain was self-quantified via the Visual Analogue Scale (VAS), and the Clinical Global Impression Scale for Severity of illness (CGI-S) helped in evaluating the oral general conditions. This study is listed on the ISRCTN registry. At t3, the QGBI, MGI, OH-15, VAS, and CGI-S values decreased in the treated but not in the placebo group (β = 0.6 ± 0.1, t176 = 3.680, p < 0.001; β = 0.87 ± 0.21, t115 = 4.263, p < 0.001; β = 5.3 ± 2.5, t172 = 2.086, p = 0.038; β = 3.16 ± 0.51, t88 = 6.253, p < 0.001; and β = 1.09 ± 0.32, t83 = 3.419, p < 0.001, respectively). A significant improvement in gingival health occurred after a 3-month intervention with the chewing gums containing S. lateriflora and C. incanus extracts.
Responsive Feeding Practices to Promote Healthy Diets: A Mixed Method Study among Low-Income Caregivers with Toddlers
Authors: Killion Kate E. , Corcoran Amy , Romo-Palafox Maria J. , Harris Jennifer L. , Kagan Inna , Gilbert Laura , Duffy Valerie B.
Published: March 2024

Responsive feeding (RF), the reciprocal feeding approach between caregiver and child that promotes child health, is understudied among low-income caregivers. This mixed methods study with low-income caregivers of 12-to-36-month-olds aimed to (1) assess variability in RF and associations with children’s dietary intake, and (2) explore caregivers’ perceptions of RF. Caregivers (n = 134) completed an online survey with RF questions (n = 25), grouped into environmental (meal environment, caregiver modeling, caregiver beliefs) and child (self-regulation, hunger/satiety cues, food for reward, food acceptance) influences scores. Children’s recent food group consumption was loaded onto healthy and less healthy intake scores. In an adjusted multiple linear regression analysis, greater RF scores for environmental and child influences were associated with greater healthy intake scores (p’s < 0.01). Greater scores for environmental influences were also associated with lower scores for unhealthy intake (p < 0.01). From focus groups with a separate sample of caregivers (n = 24), thematic analysis uncovered that two themes aligned (trust in child cues, positive strategies to encourage children to eat non-preferred foods) and two misaligned (lack of trust in child cues, use of force/bribery) with RF. Complementary integration of quantitative and qualitative findings can inform future interventions with low-income caregivers, encouraging trust in young children’s hunger/satiety cues and positive strategies for food acceptance to improve diet quality.
Vitamin D Status in the Adult Population of Romania—Results of the European Health Examination Survey
Authors: Brîndușe Lăcrămioara Aurelia , Eclemea Irina , Neculau Andrea Elena , Cucu Maria Alexandra
Published: March 2024

Background: Vitamin D deficiency is recognized as a general health condition globally and is acknowledged as a public health concern in Europe. In Romania, a national program of examination of the status of vitamin D for high-risk groups has demonstrated a vitamin D deficiency prevalence of 39.83%. No national data on the status of vitamin D in the general adult population are available to date. Methods: We used the framework of the European Health Examination Survey to analyze vitamin D levels in a sample population of adults aged 25–64 years, from 120 family doctors’ patients lists, by using a sequential sampling method. Data were weighted to the Romanian population. Vitamin D deficiency was defined as 25(OH)D < 20 ng/mL. Results: In total, 5380 adults aged 25–64 years were included in this study. The overall prevalence of vitamin D deficiency is 24.8%. Predictors of vitamin D deficiency were found to be obesity, female sex, living in rural areas, lower education level, and lower socioeconomic status. Conclusions: Specific recommendations for vitamin D screening and supplementation should be issued for women by specialist boards. Further studies are needed to identify seasonal variation and to establish a correlation with nutritional surveys.
Nutrition-Related Knowledge, Attitudes, Practices, and Anemia Status of Lactating Mothers in Bukavu, Democratic Republic of the Congo—A Cross-Sectional Analysis
Authors: Beitze Damaris Elisabeth , Kavira Malengera Céline , Barhwamire Kabesha Theophile , Scherbaum Veronika
Published: March 2024

Maternal nutrition is impacted by personal and environmental factors including dietary intake, knowledge, food availability, and affordability. This cross-sectional analysis aimed to evaluate nutrition-related knowledge, attitudes, practices, and associations with hemoglobin concentration among lactating mothers in the Bukavu region, Democratic Republic of the Congo. In 444 lactating mothers, nutrition-related knowledge and practice were assessed by questionnaires and translated into knowledge and practice scores ranging from 0 to 1, attitudes and drivers of food choice were assessed, the Dietary Diversity Score (DDS) was assessed with 24 h dietary recalls in a potential range from 0 to 10, and hemoglobin (Hb) was measured in mothers and their infants. Anemia prevalence was 28.2% among mothers and 74.3% among infants aged 3–8 months. Nutritional knowledge and practice were limited (the median total knowledge score was 0.39, median DDS was 3.0). While there were slight positive correlations between knowledge and maternal Hb, DDS did not significantly correlate with either knowledge or Hb. Although half of the mothers stated a perception about their own susceptibility to anemia or vitamin A deficiency (56.4%, 47.4%), less than half of those could justify their estimation (40.9%, 44.2%). Taste (68.1%), appearance (42.5%), availability (29.0%), and health effects (25.6%) were important drivers of food choice. In conclusion, interventions on the different influencing factors including nutrition education strategies are needed.
The Association between Molecular Initiating Events and Drug-Induced Hiccups
Authors: Hosoya Ryuichiro , Ishii-Nozawa Reiko , Terajima Tomoko , Kagaya Hajime , Uesawa Yoshihiro
Published: March 2024

Hiccups can significantly reduce the quality of life of patients and can occur as a drug side effect. Previous reports have revealed sex-specific differences in the incidence of drug-induced hiccups. However, the pathogenesis of drug-induced hiccups remains unknown, and there is limited evidence on its treatment or prevention. This study examined molecular initiating events (MIEs), which are the starting point of adverse events, to investigate the drug-induced pathways of hiccups. We extracted drugs suspected to cause hiccups using the FDA Adverse Event Reporting System, a large database on adverse drug reactions. Information on drugs suspected to be associated with hiccups was extracted from the overall population and sex-specific subgroups were divided. In each data table, the predicted activity values of nuclear receptors and stress response pathways for each drug were calculated using the Toxicity Predictor, a machine-learning model. Transforming growth factor-beta and antioxidant response elements were considered an independent factor for hiccups in the male and female subgroups, respectively. This report first examined one of the mechanisms of drug-induced hiccups and identified MIEs associated with drug-induced hiccups. The use of an adverse event database and the machine-learning model, Toxicity Predictor, may be useful for generating hypotheses for other adverse effects with unknown mechanisms.
Aztreonam Combinations with Avibactam, Relebactam, and Vaborbactam as Treatment for New Delhi Metallo-β-Lactamase-Producing Enterobacterales Infections—In Vitro Susceptibility Testing
Authors: Brauncajs Małgorzata , Bielec Filip , Malinowska Marlena , Pastuszak-Lewandoska Dorota
Published: March 2024

Antimicrobial resistance is a major global health issue. Metallo-β-lactamases (MBL), in particular, are problematic because they can inactivate all classes of β-lactams except aztreonam. Unfortunately, the latter may be simultaneously inactivated by serine β-lactamases. The most dangerous known MBL is New Delhi Metallo-β-lactamase (NDM). This study aimed to test the in vitro susceptibility to aztreonam in combination with novel β-lactamase inhibitors (avibactam, relebactam, and vaborbactam) in clinical strains of Enterobacterales NDM which is resistant to aztreonam. We investigated 21 NDM isolates—including Klebsiella pneumoniae, Escherichia coli, and Citrobacter freundii—which are simultaneously resistant to aztreonam, ceftazidime/avibactam, imipenem/relebactam, and meropenem/vaborbactam. MICs for aztreonam combinations with novel inhibitors were determined using the gradient strip superposition method. The most effective combination was aztreonam/avibactam, active in 80.95% strains, while combinations with relebactam and vaborbactam were effective in 61.90% and 47.62%, respectively. In three studied strains, none of the studied inhibitors restored aztreonam susceptibility. Aztreonam/avibactam has the most significant antimicrobial potential for NDM isolates. However, combinations with other inhibitors should not be rejected in advance because we identified strain susceptible only to tested combinations with inhibitors other than avibactam. Standardization committees should, as soon as possible, develop official methodology for antimicrobial susceptibility testing for aztreonam with β-lactamase inhibitors.
Transcriptome-Wide 5-Methylcytosine Profiling of lncRNAs in the Mouse Cerebral Ischemia Model
Authors: Zhang Chao , Gao Junpeng , Xiong Dan , Zhao Yan
Published: March 2024

An increasing body of research has demonstrated the significant role of long non-coding RNAs (lncRNAs) in the pathogenesis of stroke. They can actively contribute to the disease’s progression either by directly participating in its pathogenesis or by acting as mediators through competing endogenous RNA (ceRNA) mechanisms. Concurrently, epigenetics plays a pivotal role in the pathological mechanisms underlying stroke. Epigenetic factors serve as valuable markers for disease progression, diagnostic biomarkers, and novel therapeutic targets. One of the most prevalent epigenetic modifications is 5-methylcytosine (m5C). However, the specific profiles of 5-methylcytosine in lncRNAs associated with stroke remain to be solved. Within the scope of this research, we performed a thorough transcriptome-wide analysis of m5C methylation within lncRNAs by methylated RNA immunoprecipitation sequencing (MeRIP-Seq), within a mouse stroke model induced by middle cerebral artery occlusion. Our findings reveal substantial disparities in both the quantity and distribution of m5C within the mouse stroke model compared to normal mice. This suggests a potential linkage between stroke and lncRNA m5C modifications, offering valuable insights into the mechanisms of stroke pathogenesis and the development of new drug targets.
Earth-Bound Preaching: Engaging Scripture, Context, and Indigenous Wisdom
Authors: Kim-Cragg HyeRan
Published: March 2024

In developing an Earth-bound homiletics, three homiletical movements are suggested: engaging Scripture, engaging global and local situatedness, and engaging the Indigenous worldview of “all my relations” by tapping into Indigenous knowledge. These three movements need not take place in any chronological order, nor should they be seen as a hierarchy. Rather, they are complementary and interconnected. The author, before articulating these movements, offers reasons for why the topic of the climate crisis is not preached on and then addresses the challenge of selecting biblical texts, delineating the strengths and weaknesses of using the lectionary readings versus a preacher’s individual choices. The article further addresses the danger of biblical literalists who deny global warming. Each homiletical movement will be elaborated using actual sermons as concrete examples of Earth-bound homiletics.
Good News for the Oppressed? Exploring the Spiritual, Political, and Intercultural Dimensions of Howard Thurman’s Philosophy
Authors: Yong Aizaiah G.
Published: March 2024

This paper centers on the godfather of the civil rights movement, Howard Thurman, and his most influential work, “Jesus and the Disinherited”, as a pre-eminent text into early 20th century intercultural philosophy. Building upon Kipton Jensen’s analysis in “Howard Thurman: Philosophy, Civil Rights, and the Search for Common Ground”, this presentation will reframe Howard Thurman’s unique philosophy as one that integrates spirituality, interculturality, and critical social analysis. It is well known that Thurman’s treatise on the oppressed was carried in the pocket of Rev. Dr. Martin Luther King Jr. throughout the civil rights movement for the ways it empowered nonviolent resistance for those marginalized by the dominant culture of the United States, which was (and still is) built on racism, military violence, and class-based oppression. This paper advocates that Thurman came to his philosophical conclusions through deep engagement with various cultural and philosophical traditions, most notably the Hindu spiritual–political paradigm of Mahatma Gandhi, and sought to harmonize these insights for African Americans in the USA. By investigating the intercultural foundations of “Jesus and the Disinherited”, this paper will encourage scholars to explore how interculturality enriched Thurman’s philosophy and how this fostered a more expansive vision of community in pluralistic societies. This article traces the roots of the development of “Jesus and the Disinherited”, looking back to presentations Thurman gave as early as 1922, concluding with the publication of his book in 1949. And via this study, we will see the progression of Thurman’s ideas and the impacts interculturality had on his philosophy and vision for social justice.
The Amazon’s 2023 Drought: Sentinel-1 Reveals Extreme Rio Negro River Contraction
Authors: Wagner Fabien H. , Favrichon Samuel , Dalagnol Ricardo , Hirye Mayumi C. M. , Mullissa Adugna , Saatchi Sassan
Published: March 2024

The Amazon, the world’s largest rainforest, faces a severe historic drought. The Rio Negro River, one of the major Amazon River tributaries, reached its lowest level in a century in October 2023. Here, we used a U-net deep learning model to map water surfaces in the Rio Negro River basin every 12 days in 2022 and 2023 using 10 m spatial resolution Sentinel-1 satellite radar images. The accuracy of the water surface model was high, with an F1-score of 0.93. A 12-day mosaic time series of the water surface was generated from the Sentinel-1 prediction. The water surface mask demonstrated relatively consistent agreement with the global surface water (GSW) product from the Joint Research Centre (F1-score: 0.708) and with the Brazilian MapBiomas Water initiative (F1-score: 0.686). The main errors of the map were omission errors in flooded woodland, in flooded shrub, and because of clouds. Rio Negro water surfaces reached their lowest level around the 25th of November 2023 and were reduced to 68.1% (9559.9 km2) of the maximum water surfaces observed in the period 2022–2023 (14,036.3 km2). Synthetic aperture radar (SAR) data, in conjunction with deep learning techniques, can significantly improve near-real-time mapping of water surfaces in tropical regions.
A Unitary Transformation Extension of PolSAR Four-Component Target Decomposition
Authors: Wang Tingting , Suo Zhiyong , Ti Jingjing , Yan Boya , Xiang Hongli , Xi Jiabao
Published: March 2024

As an improvement on the traditional model-based Yamaguchi four-component decomposition method, in recent years, to fully utilize the polarization information in the coherency matrix, four-component target decomposition methods Y4R and S4R have been proposed, which are based on the rotation of the coherency matrix and the expansion of the volume model, respectively. At the same time, there is also an improved G4U method proposed based on Y4R and S4R. Although these methods have achieved certain decomposition results, there are still problems with overestimation of volume scattering and insufficient utilization of polarization information. In this paper, a unitary transformation extension to the four-component target decomposition method of PolSAR based on the properties of the Jacobi method is proposed. By analyzing the terms in the basic scattering models, such as volume scattering, in the existing four-component decomposition methods, it is clear that the reason for the existence of the residual matrix in the existing decomposition methods is that the off-diagonal term T13 and the real part of T23 of the coherency matrix T do not participate in the four-component decomposition. On this basis, a matrix transformation method is proposed to decouple terms T13 and ReT23, and the residual matrix decomposed based on this method is derived. The performance of the proposed method was validated and evaluated using two datasets. The experimental results indicate that, compared with model-based methods such as Y4R, S4R and G4U, the proposed method can enhance the contribution of double-bounce scattering and odd-bounce scattering power in urban areas in both sets of data. The computational time of the proposed method is equivalent to Y4R, S4R, etc.
Human and Small Animal Detection Using Multiple Millimeter-Wave Radars and Data Fusion: Enabling Safe Applications
Authors: Mattos Ana Beatriz Rodrigues Costa De , Brante Glauber , Moritz Guilherme L. , Souza Richard Demo
Published: March 2024

Millimeter-wave (mmWave) radars attain high resolution without compromising privacy while being unaffected by environmental factors such as rain, dust, and fog. This study explores the challenges of using mmWave radars for the simultaneous detection of people and small animals, a critical concern in applications like indoor wireless energy transfer systems. This work proposes innovative methodologies for enhancing detection accuracy and overcoming the inherent difficulties posed by differences in target size and volume. In particular, we explore two distinct positioning scenarios that involve up to four mmWave radars in an indoor environment to detect and track both humans and small animals. We compare the outcomes achieved through the implementation of three distinct data-fusion methods. It was shown that using a single radar without the application of a tracking algorithm resulted in a sensitivity of 46.1%. However, this sensitivity significantly increased to 97.10% upon utilizing four radars using with the optimal fusion method and tracking. This improvement highlights the effectiveness of employing multiple radars together with data fusion techniques, significantly enhancing sensitivity and reliability in target detection.
Comparing Video Analysis to Computerized Detection of Limb Position for the Diagnosis of Movement Control during Back Squat Exercise with Overload
Authors: Peres André B. , Sancassani Andrei , Castro Eliane A. , Almeida Tiago A. F. , Massini Danilo A. , Macedo Anderson G. , Espada Mário C. , Hernández-Beltrán Víctor , Gamonales José M. , Pessôa Filho Dalton M.
Published: March 2024

Incorrect limb position while lifting heavy weights might compromise athlete success during weightlifting performance, similar to the way that it increases the risk of muscle injuries during resistance exercises, regardless of the individual’s level of experience. However, practitioners might not have the necessary background knowledge for self-supervision of limb position and adjustment of the lifting position when improper movement occurs. Therefore, the computerized analysis of movement patterns might assist people in detecting changes in limb position during exercises with different loads or enhance the analysis of an observer with expertise in weightlifting exercises. In this study, hidden Markov models (HMMs) were employed to automate the detection of joint position and barbell trajectory during back squat exercises. Ten volunteers performed three lift movements each with a 0, 50, and 75% load based on body weight. A smartphone was used to record the movements in the sagittal plane, providing information for the analysis of variance and identifying significant position changes by video analysis (p < 0.05). Data from individuals performing the same movements with no added weight load were used to train the HMMs to identify changes in the pattern. A comparison of HMMs and human experts revealed between 40% and 90% agreement, indicating the reliability of HMMs for identifying changes in the control of movements with added weight load. In addition, the results highlighted that HMMs can detect changes imperceptible to the human visual analysis.
Elastic Tactile Sensor Glove for Dexterous Teaching by Demonstration
Authors: Ruppel Philipp , Zhang Jianwei
Published: March 2024

We present a thin and elastic tactile sensor glove for teaching dexterous manipulation tasks to robots through human demonstration. The entire glove, including the sensor cells, base layer, and electrical connections, is made from soft and stretchable silicone rubber, adapting to deformations under bending and contact while preserving human dexterity. We develop a glove design with five fingers and a palm sensor, revise material formulations for reduced thickness, faster processing and lower cost, adapt manufacturing processes for reduced layer thickness, and design readout electronics for improved sensitivity and battery operation. We further address integration with a multi-camera system and motion reconstruction, wireless communication, and data processing to obtain multimodal reconstructions of human manipulation skills.
Reliability Evaluation Method for Array Antenna Considering Performance Changes
Authors: Huang Xinxin , Zhu Sai , Liang Guanhui
Published: March 2024

The existing array antenna reliability evaluation method based on the n/k system is analyzed. As the failed T/R module’s influence on the array antenna’s performance is not considered, the reliability of the array antenna is overestimated. To improve the accuracy of the array antenna reliability evaluation, the performance changes caused by T/R failures in different locations are considered. The reliability evaluation method considering the performance changes is established. The performance and probability of the array antenna’s state are calculated, and accurate reliability is obtained by calculating all the available state’s probabilities. The complexity of the reliability evaluation method is analyzed, and the reliability evaluation method for large-scale array antennae is established. The large-scale array antenna is divided into several subarrays. The performance and reliability of each subarray are analyzed, and the array antenna’s reliability is calculated through subarrays. The array antenna’s performance changes are considered with the proposed method, the overestimation problem of the existing reliability evaluation method is solved, and the accuracy of the array antenna reliability evaluation is improved.
The Design and Implementation of a Phased Antenna Array System for LEO Satellite Communications
Authors: Adomnitei Cezar-Ion , Lesanu Cezar-Eduard , Done Adrian , Yu Ang , Dimian Mihai , Lavric Alexandru
Published: March 2024

LEO satellite constellations can provide a viable alternative to expand connectivity to remote, isolated geographical areas and complement existing IoT terrestrial communication infrastructures. This paper aims to improve LEO satellite communications by implementing a new phased antenna array system that can significantly improve the radio communication link’s performance. By adjusting the progressive phase shift to each element of the antenna array system, the direction of the main radiation lobe of the phased antenna array system can be controlled with accuracy. As far as we know, it is the first time that a four-element, three-quarter wavelength phased antenna array system has been successfully realized with the intention of being optimized for implementation in LEO IoT satellite reception systems. The proposed system’s high level of performance is confirmed by the measurements, which indicate effective control of the main radiation lobe orientation. The numerical analysis shows a maximum gain close to 12 dBi for about 42° elevation, a Half Power Beamwidth (HPBW) of 32° in the vertical plane, and 80° in the azimuth plane. The experimental measurement results at various main lobe orientation angles revealed an HPBW ranging from 76° to 87° in the azimuth plane and a maximum Front-to-Back ratio (F/B) of 14.5 dB.
Assistance Device Based on SSVEP-BCI Online to Control a 6-DOF Robotic Arm
Authors: Albán-Escobar Maritza , Navarrete-Arroyo Pablo , De la Cruz-Guevara Danni Rodrigo , Tobar-Quevedo Johanna
Published: March 2024

This paper explores the potential benefits of integrating a brain–computer interface (BCI) utilizing the visual-evoked potential paradigm (SSVEP) with a six-degrees-of-freedom (6-DOF) robotic arm to enhance rehabilitation tools. The SSVEP-BCI employs electroencephalography (EEG) as a method of measuring neural responses inside the occipital lobe in reaction to pre-established visual stimulus frequencies. The BCI offline and online studies yielded accuracy rates of 75% and 83%, respectively, indicating the efficacy of the system in accurately detecting and capturing user intent. The robotic arm achieves planar motion by utilizing a total of five control frequencies. The results of this experiment exhibited a high level of precision and consistency, as indicated by the recorded values of ±0.85 and ±1.49 cm for accuracy and repeatability, respectively. Moreover, during the performance tests conducted with the task of constructing a square within each plane, the system demonstrated accuracy of 79% and 83%. The use of SSVEP-BCI and a robotic arm together shows promise and sets a solid foundation for the development of assistive technologies that aim to improve the health of people with amyotrophic lateral sclerosis, spina bifida, and other related diseases.
A Real-Time Monitoring Method for Droplet Transfer Frequency in Wire-Filled GTAW Based on Arc Sensing
Authors: Jia Aiting , Luo Yifang , Hong Bo , Li Xiangwen , Yin Li , Luo Mina
Published: March 2024

Droplet transfer frequency is a decisive factor in welding quality and efficiency in gas tungsten arc welding (GTAW). However, there still needs to be a monitoring method for droplet transfer frequency with high precision and good real-time performance. Therefore, a real-time monitoring method for droplet transfer frequency in wire-filled GTAW using arc sensing is proposed in this paper. An arc signal acquisition system is developed, and the wavelet filtering method filters out noise from the arc signal. An arc signal segmentation method—based on the OTSU algorithm and a feature extraction method for droplet transition based on density-based spatial clustering of applications with noise (DBSCAN)—is proposed to extract the feature signal of the droplet transition. A new conception of droplet transition uniformity is proposed, and it can be used to monitor the weld bead width uniformity. Numerous experiments for monitoring droplet transfer frequency in real time are conducted with typical welding parameters. This method enables the real-time observation of droplet transfer frequency, and the result shows that the average monitoring error is less than 0.05 Hz.
Machine Learning in Communication Systems and Networks
Authors: Sun Yichuang , Lee Haeyoung , Simpson Oluyomi
Published: March 2024

The landscape of communication environments is undergoing a revolutionary transformation, driven by the relentless evolution of technology and the growing demands of an interconnected world [...]
Detection of a Submillimeter Notch-Type Defect at Multiple Orientations by a Lamb Wave A0 Mode at 550 kHz for Long-Range Structural Health Monitoring Applications
Authors: Capineri Lorenzo , Taddei Lorenzo , Marino Merlo Eugenio
Published: March 2024

The early detection of small cracks in large metal structures is a crucial requirement for the implementation of a structural health monitoring (SHM) system with a low transducers density. This work tackles the challenging problem of the early detection of submillimeter notch-type defects with a semielliptical shape and a groove at a constant width of 100 µm and 3 mm depth in a 4.1 mm thick aluminum plate. This defect is investigated with an ultrasonic guided wave (UGW) A0 mode at 550 kHz to investigate the long range in thick metal plates. The mode selection is obtained by interdigital transducers (IDTs) designed to operate with a 5 mm central wavelength. The novel contribution is the validation of the detection by pulse-echo and pitch and catch with UGW transducers to cover a distance up to 70 cm to reduce the transducers density. The analysis of scattering from this submillimeter defect at different orientations is carried out using simulations with a Finite Element Model (FEM). The detection of the defect is obtained by comparing the scattered signals from the defect with baseline signals of the pristine laminate. Finally, the paper shows that the simulated results are in good agreement with the experimental ones, demonstrating the possible implementation in an SHM system based on the efficient propagation of an antisymmetric mode by IDTs.
CoFe2O4 on Mica Substrate as Flexible Ethanol Gas Sensor in Self-Heating Mode
Authors: Kim Jong Hun , Choi Yeong Uk , Jung Jong Hoon , Kim Jae-Hun
Published: March 2024

In this study, a novel flexible ethanol gas sensor was created by the deposition of a CoFe2O4 (CFO) thin film on a thin mica substrate using the pulsed laser deposition technique. Transition electron microscopy (TEM) investigations clearly demonstrated the successful growth of CFO on the mica, where a well-defined interface was observed. Ethanol gas-sensing studies showed optimal performance at 200 °C, with the highest response of 19.2 to 100 ppm ethanol. Operating the sensor in self-heating mode under 7 V applied voltage, which corresponds to a temperature of approximately 200 °C, produced a maximal response of 19.2 to 100 ppm ethanol. This aligned with the highest responses observed during testing at 200 °C, confirming the sensor’s accuracy and sensitivity to ethanol under self-heating conditions. In addition, the sensor exhibited good selectivity to ethanol and excellent flexibility, maintaining its high performance after bending and tilting up to 5000 times. As this is the first report on flexible self-heated CFO gas sensors, we believe that this research holds great promise for the future development of high-quality sensors based on this approach.
Spatial and Temporal Variation of Urban Heat Islands in French Guiana
Authors: Ilunga Gustave , Bechet Jessica , Linguet Laurent , Zermani Sara , Mahamat Chabakata
Published: March 2024

A surface urban heat island (SUHI) is a phenomenon whereby temperatures in urban areas are significantly higher than that of surrounding rural and natural areas due to replacing natural and semi-natural areas with impervious surfaces. The phenomenon is evaluated through the SUHI intensity, which is the difference in temperatures between urban and non-urban areas. In this study, we assessed the spatial and temporal dynamics of SUHI in two urban areas of the French Guiana, namely Ile de Cayenne and Saint-Laurent du Maroni, for the year 2020 using MODIS-based gap-filled LST data. Our results show that the north and southwest of Ile de Cayenne, where there is a high concentration of build-up areas, were experiencing SUHI compared to the rest of the region. Furthermore, the northeast and west of Saint-Laurent du Maroni were also hotspots of the SUHI phenomenon. We further observed that the peak of high SUHI intensity could reach 5 °C for both Ile de Cayenne and Saint-Laurent du Maroni during the dry season when the temperature is high with limited rainfall. This study sets the stage for future SUHI studies in French Guiana and aims to contribute to the knowledge needed by decision-makers to achieve sustainable urbanization.