Level Set Research Articles

Comparative Analysis Of Energy Expenditure Assessments From The Graded Exercise Test Vs. Galaxy Watch And Apple Watch In Korean College Students During A 30-minute Workout: A Pilot Study

OBJECTIVES In the modern era, there is heightened interest in understanding energy expenditure during exercise. Consequently, wearable devices such as the Galaxy Watch and Apple Watch have emerged as pivotal tools for daily health monitoring, given their convenience and increasing popularity. This study aimed to compare the calculated energy expenditure derived from the graded exercise test with readings from Galaxy and Apple Watches during a 30-min exercise session among Korean university students. Through this, we anticipate offering both motivation and clear insights into energy expenditure, thereby potentially aiding in weight management strategies for contemporary individuals.METHODS This study involved 27 college students from Korea National University of Transportation in Chungcheongbuk-do, Korea. We utilized COSMED's exercise load respiratory gas analysis system (Quark- CPET, COSMED, Rome, Italy), along with the Galaxy Watch (Galaxy Watch 5, Samsung, Seoul, Korea) and the Apple Watch (Apple watch series 5, Apple, Cupertino, USA) for measurements. Energy expenditure was monitored in real-time every 5 min throughout the 30-min exercise session. For statistical evaluations, we employed a one-way analysis of variance. Subsequent post-tests utilized the Tukey post-hoc test and Pearson correlation, with a significance level set at p<0.05.RESULTS Initially, no statistically significant difference emerged between energy expenditure readings from the graded exercise test and those from the Galaxy Watch across all time intervals: 5, 10, 15, 20, 25, and 30 min (p>0.05). Conversely, a notable difference was observed when comparing energy expenditure data from the graded exercise test to that of the Apple Watch for time intervals of 10, 15, 20, 25, and 30 min (p>0.05), although the 5-min interval did not exhibit a significant difference (p>0.05). Furthermore, a robust positive correlation was evident between the energy expenditure values derived from the graded exercise test and those from both the Galaxy Watch (r=0.952, p<0.001) and the Apple Watch (r=0.917, p<0.001).CONCLUSIONS Both devices demonstrated high reliability in calculating energy expenditure. Notably, the Galaxy Watch exhibited a more precise calculation compared to the Apple Watch, with a relative reliability margin of 3.5% higher. For individuals, especially those struggling with obesity, precise wearable devices that accurately reflect energy consumption can significantly boost motivation for exercise. Consequently, this study lays a foundation for future advancements in energy expenditure measurement tools, emphasizing enhanced convenience, reliability, and mobility.

Role of Non‐Covalent Interactions on Acid Strength Measurement of Liquid Acids using Phosphine Oxide NMR Probe

AbstractThe 31P NMR Chemical Shifts(δP) of Trimethylphosphine Oxide (TMPO) conjugated with ten common liquid molecular acids have been calculated employing the Density Functional Theory (DFT) based computational method. These shifts have been correlated with the intrinsic acid strength parameter, Deprotonation Energy (DPE), of the underlying acids and the complexation energy of TMPO (ΔΕ). The acids, anions, and conjugated complexes were modeled with PW91 functional and 6‐31++G(d,p) basis set. The NMR calculations were performed on the relaxed structures as single‐point calculations using the Gauge Including Atomic Orbital (GIAO) method at the MP2 level and TZVP basis set. Poor linearity was observed in the correlation of δP with respect to DPE (R2=0.867), while strong linearity was seen with the complexation energy ΔΕ (R2=0.967). We have hypothesized the unreliable modeling of anions and Non‐Covalent Interactions (NCI) to be the factors affecting the linear trend of δP with respect to DPE. To support our hypothesis, we have presented Reduced Density Gradient (RDG) Maps and 31P NMR Tensor spatial orientation data of the Acid‐TMPO conjugates.

Evaluation of optimal interpolation and segmentation of the optic nerves on magnetic resonance images for cross‐sectional area measurement

AbstractThis study investigated nine combination methods produced from three interpolation (Lanczos, iterative curvature based interpolation, and contrast‐guided) and three segmentation (spatial fuzzy C‐means, modified fuzzy C‐means [mFCM], and level set method) models from optic nerve magnetic resonance images (MRI). The aim was to produce sharp edges of the optic nerves for cross‐sectional area measurement. Lanczos‐mFCM was identified as the best combination in terms of: image quality; Dice similarity coefficient; a similar area compared with measurements from raw images but with higher reproducibility; and the highest signal‐to‐noise and contrast‐to‐noise ratios. It was then applied to ten normal datasets. The mean cross‐sectional areas were 12.57 ± 1.92mm2 from proton density images, 12.98 ± 2.18mm2 from T2‐weighted (T2W) images including the optic nerve sheath, and 1.68 ± 0.69mm2 from the T2W images of the optic nerve only. The Lanczos‐mFCM method is recommended for future quantitative studies on optic nerve MRI.

Incidence and Causes of Discharging Ear after Mastoid Exploration

Background: Chronic ear diseases, common in developing countries, often require mastoid exploration, leading to post-operative ear discharge. This study, conducted at ENT Unit I of Jinnah Hospital (November 2022 to November 2023), investigates postoperative ear discharge incidences across different mastoid exploration techniques. Objective: This cross-sectional study conducted at ENT Unit I of Jinnah Hospital, Lahore, from November 2022 to November 2023 aimed to investigate the incidence of post-operative ear discharge following different mastoid exploration techniques. The study sought to establish associations between surgical techniques and post-operative outcomes, including the nature of discharge and causative organisms.– Methods: A sample of 18 ears, systematically divided into three groups based on the surgical technique. The groups included Cortical Mastoidectomy (Group A), Radical Mastoidectomy (Group B), and Modified Radical Mastoidectomy (Group C). Purposive sampling was employed, and data were collected from patient records, including demographic information, surgicaltechniques, and culture results of ear discharge samples. Statistical analysis, including chi-square tests and Fisher's exact tests, was conducted to determine associations, with a significance level set at 0.05 Results: Incidence rates for Groups A, B, and C were 66.67%, 100%, and 54.55%, resulting in an overall incidence of 55.17% Microbiological analysis revealed prevalent causative organisms, including Pseudomonas aeruginosa and Staphylococcus aureus. Statistical analysis confirmed a significant association between surgical technique and outcomes. Conclusion: The study underscores the significance of tailoring mastoid exploration techniques to minimize post-operative ear discharge. Understanding the microbiological profile enhances targeted interventions for better patient outcomes.

Investigating the Effect of Internal Bleaching With 10% Carbamide Peroxide on the Color Change of Three Types of Common Endodontic Sealers.

Background and purpose Color change caused by materials used for endodontic treatment is an important clinical issue. The current research examined the impact of internal bleaching with 10% carbamide peroxide on discolored teeth resulting from various types of sealers. Materials and methods In this study, 36 anterior teeth were cut from 1 mm beneath the cementoenamel junction (CEJ), and the samples were divided into three groups of 12. Then, AH26 (Tulsa Dental, Tulsa, OK), Endofill (Herpo Produtos Dentários Ltda, Petrópolis, Brazil), and AH Plus (DentsplyDeTrey, Konstanz, Germany) color change potential sealers were placed inside the pulp chamber. The cervical access cavity was covered with a thin layer of glass ionomer. After one month, the material was removed, and bleaching was done with 10% carbamide peroxide. The color of the samples was measured by a spectrophotometer before bleaching, one week after bleaching, and one week after bleaching again. The data were subjected to statistical analysis using the Statistical Package for Social Sciences (SPSS)software version 16 (IBM SPSS Statistics, Armonk, NY), with a significance level set at P<0.05. Results The results showed that the factor of time and material used and the opposing effect of these two on the amount of L and ΔE were statistically significant (P<0.05). After one to two weeks of internal bleaching, all groups showed some degree of reduction in sealer-induced discoloration. In addition, in all groups, the largest difference in L was related to the difference in L0 and L2 (before bleaching and one week after bleaching again), and the lowest difference was related to the difference in L0 and L1. Also, the highest ΔE(T0,T1) belonged to the Endofill group, and this significantly differed from the AH26 group. AH26 showed the lowest value of ΔE(T0,T1), and after two weeks, the ΔE of all groups was higher than the clinically observable limit. The highest ΔE(T2,T0) among the groups belonged to the Endofill group. The ΔE(T2,T0) of AH26 and Endofill was significantly higher than AH Plus. Among all ΔE values, the AH Plus group had the lowest values. Conclusion Color change caused by Endofill and AH26 sealers showed a better response to internal bleaching than the AH Plus sealer.

Comparison of Joint Position Sense and Force-Reproduction in Female Racquet Athletes with and Without Scapular Dyskinesia

Background: Scapular dyskinesia (SD) is a common condition that affects racquet athletes, impacting their performance and predisposing them to injuries. Objectives: This study aimed to compare joint position sense (JPS) and force reproduction in racquet athletes with and without SD. Methods: This study was conducted as a cross-sectional study. The statistical population consisted of female student-athletes aged 18 to 30 who were engaged in badminton, tennis, and ping pong in Quchan city, both with and without shoulder dyskinesia. The sample included thirty athletes with shoulder dyskinesia and thirty without it, who were randomly selected. Joint Position Sense was assessed at 45 and 135 degrees of abduction. The tools employed in this research encompassed a consent form, an inclinometer (goniometer), the Kibler test, force-reproduction testing, and the McClure test. Data analysis was performed using the Shapiro-Wilk test and an independent t-test in SPSS version 23, with a significance level set at P &lt; 0.05. Results: The results revealed a statistically significant difference in JPS of the shoulder joint between athletes with and without SD at angles of 45 and 135 degrees (P &lt; 0.05). Similarly, the independent t-test analysis demonstrated a significant difference in force reproduction of the shoulder joint between athletes with and without dyskinesis (P &lt; 0.05). Conclusions: These findings underscore the importance of addressing SD and its associated sensory impairments in racquet athletes to optimize performance and reduce the risk of injuries.

Epidemiology and Related Factors of Internet Addiction with Emphasizing the Role of Feeling Loneliness and Interpersonal Problems in University Students

Background: Internet addiction is recognized as a global public health issue, with high prevalence among medical students. The identification of risk factors related to Internet addiction is crucial for reducing its prevalence and severity. Objectives: This study aimed to assess the epidemiology and related factors to Internet addiction, emphasizing the role of feeling loneliness and interpersonal problems. Methods: A cross-sectional correlational study was conducted in 2022, involving 414 students from the Nursing and Midwifery Faculty, Jundishapur University of Medical Sciences, Ahvaz, Iran. Young’s Internet addiction questionnaire, along with the assessments of interpersonal problems and loneliness, was used. Descriptive and inferential statistics (including correlation coefficients and hierarchical regression) were applied using SPSS software (version 22), with a significance level set at P &lt; 0.05. Results: All students had internet addiction; nevertheless, the majority (82.4%) of them were in the range of mild addiction, and none of them had severe Internet addiction. The average score of Internet addiction was 51.59 (4.77), which shows moderate Internet addiction among students. Internet addiction had a positive and significant relationship with students’ lodging (dormitory), feelings of loneliness, and interpersonal problems; however, there was no correlation with age, gender, marital status, major, and academic year. Conclusions: The prevalence of Internet addiction was significantly higher in the present study than in previous studies, serving as a critical warning for health practitioners and planners. Notably, the highest level of addiction observed was at a mild level, necessitating early intervention to prevent further escalation. Considering the correlation between Internet addiction and students’ lodging (dormitory), feelings of loneliness, and interpersonal problems, it is imperative to explore alternative activities within dormitories and provide regular psychological counseling for the early detection of these issues.

Hole formation mechanisms in double-sided laser drilling of Ti6Al4V-C/SiC stacked materials

This is the first investigation on the potential of doubled-sided laser drilling for hole making in Ti6Al4V-C/SiC, a hard-to-machine stacked structure that holds critical significance in high-temperature structural applications. While previous literature reported laser drilling-induced microstructural change in Ti6Al4V and C/SiC single sheets respectively, a comprehensive understanding of the melt pool formation process and its influence on hole morphology/quality is still lacking. The complexity increases when Ti6Al4V is coupled with C/SiC in a stacked structure, highlighting a significant yet understudied knowledge gap in understanding the intricate material interactions at the interface. Here we present a multifaceted study combining novel computational fluid dynamics (CFD) modeling approach with ablation mechanism investigation through advanced microstructure analysis. A hybrid CFD modeling strategy integrating volume of fluid method and level set method has been developed to successfully simulate the evolution of hole shape, recast layer formation, and melt pool flow behaviour in Ti6Al4V-C/SiC. This model provides comprehensive insights into molten pool dynamics under various laser drilling conditions, fostering a fundamental understanding of the mechanism that drives recast layer formation and influencing surface quality. To validate our modeling outcomes, extensive experimental investigations were undertaken across a range of laser drilling conditions. Whenever possible, samples were analysed using advanced materials characterization techniques, including scanning electron microscopy, energy dispersive spectroscopy, and electron backscatter diffraction, to elucidate the microstructural evolution within the recast layer and the formation of the heat-affected zone. Whenever possible, the results were also compared with single side drilled Ti6Al4V-C/SiC stacks, Ti6Al4V or C/SiC single sheets (i.e., the benchmark references). Our experimental findings align well with the modeling results, systematically illustrating that doubled-sided laser drilling of the stacked structure outperforms the conventional single-sided laser drilling in terms of hole morphology, surface roughness, and reduced recast layer formation. Despite these promising results, the proposed technology is currently limited to laboratory scales and lacks capacity in manufacturing certain parts with complex geometry. Future outlook has therefore been proposed with potential solution to address these challenges and enable real world applications in future.

Screening of Prediabetic Patients by using HbA1c in District Narowal Pakistan

Background: The prevalence of prediabetes is on the rise globally, with lifestyle factors and obesity being key contributors to the development of the condition. Studies have consistently shown a link between higher Body Mass Index (BMI) and an increased risk of progressing from prediabetes to type 2 diabetes mellitus (T2DM). Objective: This study aimed to determine the prevalence of prediabetes and its association with BMI and lifestyle factors in District Narowal, Pakistan. Methods: A cross-sectional study was conducted with 200 participants from District Narowal. HbA1c levels were measured to classify participants into non-diabetic (4-7%), prediabetic (7-10%), and diabetic (10-13% and 13-16%) groups. BMI was calculated for each participant to assess weight status. Lifestyle factors were evaluated using a standardized questionnaire. Statistical analyses included the independent t-test for mean comparison and standard deviation assessment, with a significance level set at P &lt; 0.05. Results: Out of 200 participants, 81 (40.5%) were non-diabetic, 60 (30%) were prediabetic, and 16 (8%) were classified as diabetic. The mean HbA1c levels for non-diabetic, prediabetic, and diabetic individuals were 5.7%, 8.5%, and 14.5%, respectively. BMI assessment revealed that higher HbA1c levels were associated with higher BMI, and lifestyle analysis indicated a high consumption of ultra-processed foods among prediabetic individuals. Conclusion: The study found a notable prevalence of prediabetes in District Narowal, with a significant association between higher BMI and poor dietary habits with elevated HbA1c levels. These findings suggest the necessity of public health strategies focusing on weight management, nutritional education, and lifestyle modification to prevent the progression of prediabetes to T2DM.

DIAGNOSTIC ACCURACY OF MENTZER INDEX AS A SCREENING TOOL FOR THE DIAGNOSIS OF IRON DEFICIENCY ANEMIA BY TAKING IRON PROFILE AS GOLD STANDARD IN PATIENTS PRESENTING WITH HYPOCHROMIC MICROCYTIC ANEMIA AT TERTIARY CARE HOSPITAL, KARACHI

Anemia is the most prevalent haematological condition in newborns and children. A deficiency of iron necessary for synthesizing haemoglobin causes it. This study used the iron profile as the gold standard for patients with hypochromic microcytic anemia at a tertiary care hospital in Karachi to assess the Mentzer index's diagnostic accuracy for iron-deficient anemia. From January 2021 to December 2022, a cross-sectional descriptive study was conducted in the Department of Pediatrics, NICH, Karachi. With the patient's explicit consent, data was prospectively collected. Those who satisfied the diagnostic requirements totaled 163 patients. While frequency and percentages were used to represent qualitative factors, simple descriptive statistics with mean and standard deviation were used to convey quantitative data. The following metrics were calculated: diagnostic accuracy, sensitivity, specificity, positive and negative predictive values, and a significance level set at p-value ≤0.05. A total of 163 patients with hypochromic microcytic anemia were included in the study; their mean age was 8.23±3.57 years. 78 (47.9 percent) and 85 (52.1 percent) were female. For the diagnosis of iron deficiency anemia, the Mentzer index's sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were determined to be, respectively, 90.1 percent, 90.1 percent, 93.8 percent, 84.6 percent, and 90.8 percent. According to the study's findings, cell-count-based indices—in particular, the Mentzer index—are trustworthy, widely accessible techniques that have a high degree of discrimination power for identifying iron deficiency anemia.

A free boundary problem for discontinuous semilinear elliptic equations in convex ring

In this paper, we consider the following free boundary problem: ( P ) { Δ u = λ ϕ ( x ) ∑ i = 1 n H ( u − μ i ) in Ω = Ω 2 ∖ Ω ¯ 1 , u = 0 on ∂ Ω 2 , u = M on ∂ Ω 1 . The domain Ω is a convex ring where Ω 1 and Ω 2 are bounded convex domains in R N , N ≥ 2 , H is the Heaviside step function, λ , M , μ i ( i = 1 , . . , n ) are given positive real parameters and ϕ is a given function. We show that under suitable conditions, there exists a solution to problem (P) with a convex level set. We derive also an interesting result for the convexity of the set which is delimited by the free boundary in obstacle problem when the nonlinearity is discontinuous. At last, a detailed analysis is given by a construction of function ϕ which shows that there are more solutions.

Enhancing wood to charcoal conversion efficiencies from smallholder plantation charcoal production systems: Implications for carbon emissions and sustainable livelihood benefits in North Western Ethiopia.

Charcoal production stemming from small-scale Eucalyptus camaldulensis plantations has brought about significant socio-economic benefits and improved livelihoods in Ethiopia. Nevertheless, the current practice involves the use of traditional earth mound kilns, leading to inefficiencies, reduced charcoal income, and environmental pollution. This research aims to assess charcoal conversion efficiency, perform a cost-benefit analysis, and measure gas emissions from improved charcoal-making kilns sourced from Eucalyptus camaldulensis small-scale plantations in comparison to traditional earth mound kilns in northwestern Ethiopia. A one-way analysis of variance (ANOVA) was executed, with a significance level set at 0.05. The study results indicate a significant (P < 0.001) disparity in charcoal conversion efficiency across the various tested kilns, with the ranking as follows: Green mad retort kiln (33.7%) > Casamance kiln (32.09%) > MRV steel kiln (28.25%) > traditional earth mound kilns (23.55%). The improved charcoal-making kilns enhanced wood-to-charcoal conversion efficiency by 20-43% compared to traditional earth mound kilns. In terms of financial viability, Casamance improved kilns generated the highest equivalent annual charcoal income (117,126.9 ETB/year), followed by Green Mad Retort (82,893.8 ETB/year) and MRV steel kilns (58,495.9 ETB/year). As anticipated, traditional earth mound kilns yielded the lowest net present value (47,304.3 ETB/year). Traditional earth mound kilns also exhibited significantly longer carbonization times (P < 0.001), taking 3.6 times longer than the Mark V kiln and 2 times longer than the Casamance kiln. Furthermore, the statistical analysis demonstrated that improved charcoal-making technology reduced carbon dioxide (CO2) emissions by 36.1-50.7%, carbon monoxide (CO) emissions by 39.2-54.3%, and methane (CH4) emissions by 29.6-47%. In conclusion, the use of improved charcoal-making kilns has demonstrated significant enhancements in charcoal conversion efficiency, charcoal income, and environmental sustainability. Given these positive outcomes, we strongly recommend a decisive transition from traditional to cleaner, sustainable, and less emissions-intensive charcoal making kilns.

GPU-accelerated lung CT segmentation based on level sets and texture analysis

This paper presents a novel semi-automatic method for lung segmentation in thoracic CT datasets. The fully three-dimensional algorithm is based on a level set representation of an active surface and integrates texture features to improve its robustness. The method’s performance is enhanced by the graphics processing unit (GPU) acceleration. The segmentation process starts with a manual initialisation of 2D contours on a few representative slices of the analysed volume. Next, the starting regions for the active surface are generated according to the probability maps of texture features. The active surface is then evolved to give the final segmentation result. The recent implementation employs features based on grey-level co-occurrence matrices and Gabor filters. The algorithm was evaluated on real medical imaging data from the LCTCS 2017 challenge. The results were also compared with the outcomes of other segmentation methods. The proposed approach provided high segmentation accuracy while offering very competitive performance.

Time–temperature correlations of amorphous thermoplastics at large strains based on molecular dynamics simulations

In this paper, we investigate the time–temperature correlation of amorphous thermoplastics at large strains based on coarse-grained molecular dynamics simulations. This correlation behavior is characterized by the strain hardening modulus in uniaxial tension simulations at different strain rates across the glass transition region. The temperature regime is divided into a melt zone, a glassy zone, and a transition zone between them, according to the storage modulus calculated from dynamic mechanical analysis (DMA) at small strains. In the melt zone, the existence of time–temperature superposition (TTS) at large strains is verified by constructing a master curve of the hardening modulus. The obtained shift factors are then compared to those from DMA at small strains, showing that the TTS behavior is transferable between small and large strains. In the glassy zone, the effects of time and temperature are not superposable at large strains but still can be correlated. To demonstrate this correlation behavior, we introduce a level set of the hardening modulus with a variable pair of strain rate and temperature. Pairs lying in the same level result in coincident stress–strain curves at large strains. The transferability of the correlation behavior between large and small strains is validated by comparing these stress–strain curves at small strains in the pre-yield region. In the transition zone, the correlation behavior is studied with both aforementioned methods, showing that TTS is applicable to large strains but not transferable to small strains. Finally, we propose a phenomenological constitutive model for uniaxial tension to demonstrate the time–temperature correlation at large strains, considering different constant strain rates and temperatures.

Dengue Fever Perception and Knowledge for Endemicity Control among University Students of Karachi

Objective: To determine the knowledge and the risk perception regarding dengue fever among the educated population along with their behaviors towards prevention in the backdrop of rising cases of dengue at the national level.Study Design: Cross-sectional study.Place and Duration of Study: The study was carried out at the Departments of Electrical, Software Engineering, Computer Sciences and Geophysics of Bahria University, Karachi Campus, Pakistan, from October 2021 to March 2022.Methods: With an observational analytical study design, 333 students were recruited through convenient sampling. Data were collected using a structured questionnaire. The socio-demographic traits and general information about dengue fever spread and prevention were presented in frequencies and percentages while dengue fever knowledge, risk perception, and behavior of respondents were compared using a chi-square test with the significance level set at 0.05. Results: It was found that 79.8% of the students recognized that transmission of dengue is through mosquitoes, whereas only 17.4% identified the correct species of dengue infection. Twenty-two percent knew that dengue is a viral illness. Sixty-eight percent marked contaminated water as a mosquito breeding site, while 52.8% believed it to be trash/garbage. Eighty-nine, sixty-nine and fifty-two percent reported the use of window screens, bed nets/mesh, and insect repellents as protective measures, respectively. Fifty-seven percent of participants considered dengue a fatal illness. Eighty-eight and seventy-five percent recognized dengue as a preventable and curable disease, respectively. Conclusion: Educated participants in this study were misapprehensive that they had satisfactory knowledge, risk perception, and behavior toward dengue fever. Very few had the correct knowledge regarding transmission mode and spread and protective and preventive strategies. Information regarding transmission mode and spread, as well as protective and preventive strategies, were insufficient.&#x0D; How to cite this: Qureshi FM, Bari SF, Wazir SM, Wazir M, Zehra S, Khalid A. Dengue Fever Perception and Knowledge for Endemicity Control among University Students of Karachi Life and Science. 2024; 5(1): 75-82. doi: http://doi.org/10.37185/LnS.1.1.373

A Non-Traditional Finite Element Method for Scattering by Partly Covered Grooves with Multiple Media

We present a non-traditional finite element method for the electromagnetic scattering of the partly covered groove filled with multiple media. The non-local boundary condition is introduced to make the unbounded scattering into a bounded domain problem. Non-body-fitted mesh is applied to save the cost of discretizing groove domain greatly. In addition, the level set functions are utilized to describe complex media interfaces and boundaries. Numerical tests demonstrate the effectiveness and second-order convergence rate of the proposed method.

Critical penetrating vibration evolution behaviors of the gas-liquid coupled vortex flow

The gas-liquid coupled vortex flow (GCVF), as a complex physical phenomenon, has been encountered in some sustainable productions, such as chemical cleaner production, continuous steel pouring processes, and energy conversion in the tidal power plant. Its critical penetrating state recognition is essential to improve sustainable production efficiency and equipment lifetime. Due to the gas-liquid coupling transport and fluid nonlinear excitation, the state recognition oriented to the GCVF critical penetrating still faces significant challenges. To address the above matter, a fluid-structure coupling modeling and solution method based on the level set and residue theorems is put forward to obtain the GCVF-induced vibration evolution mechanism at the critical penetrating state. A wavelet packet-based signal processing method is proposed to obtain the evolution law of the peak component of the GCVF-induced vibration. Research results found that the proposed modeling and method can better reveal the GCVF dynamic evolution regularities in the critical penetrating state. The GCVF-induced vibration exhibits energy peak and complex nonlinear pulse characteristics in the critical penetrating process. The relevant research work can provide multi-source sensing data support for the research and development of a fluid-induced vibration detection system, laying the foundation for sustainable metallurgy production, chemical cleaner extraction, and hydroelectric energy conversion.

Torus-like solutions for the Landau-de Gennes model. Part II: Topology of [formula omitted]-equivariant minimizers

We study energy minimization of a continuum Landau-de Gennes energy functional for nematic liquid crystals, in a three-dimensional axisymmetric domain and in a restricted class of S1-equivariant (i.e., axially symmetric) configurations. We assume smooth and nonvanishing S1-equivariant (e.g. homeotropic) Dirichlet boundary condition and a physically relevant norm constraint (the Lyuksyutov constraint) in the interior. Relying on our previous results in the nonsymmetric setting [16], we prove partial regularity of minimizers away from a possible finite set of interior singularities located on the symmetry axis. For a suitable class of domains and boundary data, we show that for smooth minimizers (torus solutions) the level sets of the signed biaxiality are generically finite unions of tori of revolution. Concerning nonsmooth minimizers (split solutions), we characterize their asymptotic behavior around any singular point in terms of explicit S1-equivariant harmonic maps into S4, whence the generic level sets of the signed biaxiality contains invariant topological spheres. Finally, in the model case of a nematic droplet, we provide existence of torus solutions, at least when the boundary data are suitable uniaxial deformations of the radial anchoring, and existence of split solutions for boundary data which are suitable linearly full harmonic spheres.

End of the Cage Age? A Study on the Impacts of the Transition from Cages on the EU Laying Hen Sector

This paper’s main objective is to assess the impacts of the ban on cages for housing laying hens, planned by the European Commission to raise animal welfare standards beyond the level set in the current legislation. The farm-level economic assessments of the ban were carried out in three stages: farm surveys and expert consultations, farm-level analyses, and aggregation to the EU-27 egg production sector. Four scenarios were constructed. All financial estimates were conducted with fixed prices from the year 2021 for which the reference scenario was built. Alternative hen-housing systems were barn (Voliera), free range, and organic. Until now, more than 50% of laying hens in the EU have already been transferred to alternative systems. The remaining part is subject to the transition. The basic assumptions included a reduction in yields due to the required lower densities and specifics of the production systems. A factor strongly differentiating the scenarios is likelihood of exists form the sector, as declared in the survey by many farmers, mainly those reaching retirement age without successors and keeping relatively small flocks of hens. The introduction of the ban will cause a decrease in egg production, varying between the scenarios. Substantial investments will be required within the range of 2–3.2 billion EUR, depending on the scenario.

Safety-Aware Hybrid Control of Airborne Wind Energy Systems

A fundamental concern in progressing airborne wind energy (AWE) operations toward commercial success is guaranteeing that safety requirements placed on the systems are met. Due to the high-dimensional complexity of AWE systems, however, formal mathematical robustness guarantees become difficult to compute. We draw on research from Hamilton–Jacobi (HJ) reachability analysis to compute an avoidance control maneuver for the path-following controller that enforces safety constraints on the system while maintaining the guidance strategy. In addition, the subzero level set of the computed value function inherent in HJ reachability analysis indicates the backward reachable set, the set of states from which it is possible to safely drive the system into a target set within a given time without entering undesirable states. Furthermore, to integrate the avoidance controller with the path-following controller, we derive the necessary switching law such that the avoidance maneuver is only initiated when a tether rupture is potentially imminent. We illustrate our results via extensive simulation-based studies.