The wick structure functions as a core component for heat pipe (HP) and stands as one of the critical factors that dictate the performance of HP. Consequently, this paper puts forward an three-segmented composite wick structure, which is manufactured using 80–100 mesh, 60–80 mesh, and 40–60 mesh copper powder. Experimentally, the influences of filling ratio as well as testing direction on the heat transport performance of HP equipped with segmented composite wick are explored, and the results are contrasted against those of HP featuring single wicks. Additionally, testing direction has a notable effect on the thermal behavior of HP. The maximum heat transfer capacity of HP using 40–60 mesh copper powder as the evaporation section (S1-P2) and that with 80–100 mesh copper powder as the evaporation section (S1-P1) are >90 W and 45 W, respectively. In comparison with S1-P1, S1-P2 has raised its maximum heat transfer capacity by 100 %, while its average thermal resistance of S1-P2 is no more than 0.028 °C/W. Compared with single wicks, the three-segmented composite wick design can effectively lower the thermal resistance of the HP while boosting the heat transfer capacity. Relevant research provides valuable references for optimizing the performance of HP.
N. Muthukumaran, B. Arulmurugan, Manikandan Manoharan
This study evaluates the compatibility of dissimilar welding between Inconel 59 and Austenitic Stainless Steel (AISI 904L) using CO₂ Laser Beam Welding. The investigation includes macro and microstructure analysis, mechanical property evaluation, and the effects of cryogenic treatment. Weld geometry was assessed macroscopically, confirming process feasibility. Microscopic analysis revealed fine equiaxed dendrites in the fusion zone with minimal secondary phase formation. XRD phase analysis confirmed phase stability, while residual stress analysis indicated reduced tensile stress in the fusion zone and compressive stress in adjacent regions. The fusion zone exhibited an average hardness of 236 HV, attributed to the refined dendritic structure. Cryogenic treatment improved weld performance, with tensile strength increasing by 5.5 % in shallow mode and 15.3 % in deep mode, alongside a 4.6 % enhancement in impact strength in deep cryogenic conditions. These results validate the feasibility of dissimilar welding between Alloy 59 and AISI 904L for applications requiring high strength and temperature resistance.
Pablo Merino-Muñoz, Felipe Hermosilla-Palma, Nicolás Gómez-Álvarez
et al.
<b>Background/Objectives</b>: Groin and hip injuries are common in sport, and muscle weakness has been identified as an intrinsic risk factor. So, analyzing the strength of the hip musculature becomes important. To date, there are no hip adductor isometric strength tests on force platforms. This study aims to analyze the intra-test reliability of a hip adductor strength test using force platforms. <b>Methods:</b> The study sample comprised 13 male professional soccer players with an average age of 22.3 ± 3 years, body mass of 75.8 ± 5.4 kg, and height of 1.8 ± 0.1 m. Assessments were conducted on a uniaxial force platform. The variables analyzed are peak force (PF), rate of force development (RFD), and impulse. Intra-test reliability was evaluated using the coefficient of variation (CV), intraclass correlation coefficient (ICC), and Bland–Altman plots. <b>Results:</b> Acceptable levels of reliability were identified solely for the variable of peak force, with CV values of D = 5.7% for the dominant profile and ND = 5.4% for the non-dominant profile. Furthermore, moderate and good relative reliability were observed in peak force for the dominant (ICC = 0.706) and non-dominant (ICC = 0.819) profiles, respectively. However, the remaining time-related variables, RFD and impulse, did not achieve acceptable levels of absolute reliability (CV > 10%) and displayed poor to moderate relative reliability. <b>Conclusions</b>: In summary, PF during the hip adductor isometric strength test demonstrated acceptable absolute and commendable relative reliability. Conversely, the time-related variables, specifically RFD and impulse, yielded unsatisfactory absolute and relative reliability levels.
Mechanics of engineering. Applied mechanics, Descriptive and experimental mechanics
This study investigates how decentralization and transparency offered by blockchain technology could revolutionize traditional finance. Even with the rise of well-known cryptocurrencies such as Bitcoin and Ethereum, a general understanding of blockchain’s influence on the financial industry is still lacking. We identified five major application cases—transparent credit scoring, effective consumer identification, expedited insurance settlements, improved cybersecurity, and the emergence of decentralized finance—where blockchain technology is well positioned to tackle persistent issues. We show how blockchain technology may address problems such as opaque credit scoring, poor customer identity, convoluted insurance settlement procedures, and susceptibility to cyberattacks by thoroughly examining various use cases. According to our research, a greater number of traditional financial institutions need to embrace and integrate blockchain innovations into their functions to promote inclusivity, transparency, and decentralization.
In response to the challenge of single navigation methods failing to meet the high precision requirements for unmanned aerial vehicle (UAV) navigation in complex environments, a novel algorithm that integrates Global Navigation Satellite System/Inertial Navigation System (GNSS/INS) navigation information is proposed to enhance the positioning accuracy and robustness of UAV navigation systems. First, the fundamental principles of Kalman filtering and its application in navigation are introduced. Second, the basic principles of Convolutional Neural Networks (CNNs) and Long Short-Term Memory (LSTM) networks and their applications in the navigation domain are elaborated. Subsequently, an algorithm based on a CNN and LSTM-assisted Kalman filtering fusion navigation is proposed. Finally, the feasibility and effectiveness of the proposed algorithm are validated through experiments. Experimental results demonstrate that the Kalman filtering fusion navigation algorithm assisted by a CNN and LSTM significantly improves the positioning accuracy and robustness of UAV navigation systems in highly interfered complex environments.
Zao pepper is a fermented type with a distinct flavor, and Zao pepper-based dishes are popular. However, in spontaneous fermentation (SF), the adverse microorganisms of Zao pepper are uncontrollable and alter the product quality. Lactic acid bacteria (LAB) inhibit the growth of harmful bacteria and endow a sour taste in SF. Therefore, the purpose of this study was to isolate autochthonic LAB from SF and through inoculated fermentation (IF) to improve Zao pepper quality. Four LAB strains were selected for probiotic experiments by sensory evaluation based on the flavor of Zao pepper in vitro. Intriguingly, Lactobacillus plantarum 5-1 showed superior safety and probiotics, with the fastest growth and acid-production rate. Moreover, the nitrite reductase viability of L. plantarum 5-1 reached 4.73 μmol/mL·h. The use of IF via L. plantarum 5-1 increased the total acid content 2-fold and reduced the nitrite content by 0.36-fold compared to SF in Zao pepper. In addition, IF improved the color and texture of Zao pepper. These results indicate that the autochthonic L. plantarum 5-1 improved the quality of Zao pepper, providing a new strategy for enhancing the stability of fermented pepper.
Serum and glucocorticoid-regulated kinase 1 (SGK1) is expressed in neuronal cells and involved in the pathogenesis of hypertension and metabolic syndrome, regulation of neuronal function, and depression in the brain. This study aims to identify the cellular mechanisms and signaling pathways of SGK1 in neuronal cells. In this study, the SGK1 inhibitor GSK650394 is used to suppress SGK1 expression in PC12 cells using an in vitro neuroscience research platform. Comparative transcriptomic analysis was performed to investigate the effects of SGK1 inhibition in nervous cells using mRNA sequencing (RNA-seq), differentially expressed genes (DEGs), and gene enrichment analysis. In total, 12,627 genes were identified, including 675 and 2152 DEGs at 48 and 72 h after treatment with GSK650394 in PC12 cells, respectively. Gene enrichment analysis data indicated that SGK1 inhibition-induced DEGs were enriched in 94 and 173 genes associated with vascular development and functional regulation and were validated using real-time PCR, Western blotting, and GEPIA2. Therefore, this study uses RNA-seq, DEG analysis, and GEPIA2 correlation analysis to identify positive candidate genes and signaling pathways regulated by SGK1 in rat nervous cells, which will enable further exploration of the underlying molecular signaling mechanisms of SGK1 and provide new insights into neuromodulation in cardiovascular diseases.
The lack of creative and interactive learning media impacts students' low learning outcomes. This study aims to develop interactive learning multimedia based on problem-based learning models in science content class V. This research belongs to the type of development research with the ADDIE model. The subjects of this study were one subject matter expert, one instructional design expert, one instructional media expert, three students for the individual test, and nine students for the small group test. The data collection method is the questionnaire/questionnaire method and the test method. The instrument used to collect data is a questionnaire. The data analysis techniques are quantitative descriptive and inferential statistical analyses (t-test). The results of the media product validity test showed that the subject matter expert test obtained a presentation of 98.6% (very good). Learning design expert is 92% (very good). Learning media expert is 95% (very good). Individual trials obtained a percentage of 91.3% (very good), and small group trials 90% (very good). In addition, problem-based learning-based interactive multimedia learning on science content shows an effect of problem-based learning-based interactive multimedia on student learning outcomes. It was concluded that multimedia could significantly increase the learning outcomes of fifth-grade elementary school students.
With a focus on the particle pollutants on the surface of silicon carbide crystal materials, this paper establishes a laser cleaning model for the fine particles found in silicon carbide crystal materials and proposes a new nanosecond green laser cleaning method assisted by airflow, which can effectively remove microparticles and the oxide layer on the substrate surface. Abaqus software and ANSYS Fluent software were used to simulate changes in the cleaning temperature field and the distribution of particles and dust during cleaning simulation, respectively. Based on the experimental research, and by using a nanosecond green laser to produce a wavelength of 532 nm, the direct irradiation of a nanosecond green laser on the surface of the element, and the particle contaminants on the surface of the silicon carbide material, optimized the process parameters to achieve a better cleaning efficiency. A green laser was used as a light source to conduct experiments to control the wind force of the gas chamber. The influence of the laser energy, scanning speed, and other parameters on the final cleaning efficiency was studied. The parameters of the silicon carbide before and after cleaning were characterized. The research shows that laser cleaning assisted with airflow is an efficient cleaning method that can be used to clean microparticles without damaging silicon carbide crystal substrate and to reduce the surface roughness of silicon carbide material from 1.63 to 0.34 μm, with an airflow of 0.2 Mpa.
Regional planning and development of urban agglomerations such as the Beijing-Tianjin-Hebei Region, the Yangtze River Delta, the Guangdong-Hong Kong-Macao Greater Bay Area and the Chengdu-Chongqing Twin Cities provide a good opportunity for fire rescue across administrative regions. This study is aimed at investigating the optimization technology of cross-regional synergistic deployment of fire stations. To achieve this aim, with the Yangtze River Delta integrated demonstration zone taken as the research object, urban fire risk was assessed by means of range standardization, iterative equations and expert scoring and weighting on the basis of population density, road density, water source distribution and urban POI data and urban remote sensing images. Besides, different fire response times were set with reference to the classified regional fire risk levels. Furthermore, the status of fire stations was evaluated based on the coverage-maximized model, and the cross-regional synergistic deployment of fire stations was optimized based on the facility point-minimized model. Finally, the deployment was tested using the maximized coverage rate. The following results were obtained: High-risk regions are mainly distributed in areas with dense population and high-rise buildings. The fire station coverage rates of single administrative regions are all lower than 80%; in contrast, 31 more regions are covered under cross-regional synergistic deployment. Based on the facility point minimization model and the maximum coverage model, on the basis of retaining the existing fire stations, when 17 new fire stations are built, 90% of the high-risk fire areas in the study area can be covered within 3 min, and the coverage of medium-risk areas and low-risk areas can be increased to 70%, which can better meet the fire risk prevention and control needs of the Yangtze River Delta integrated demonstration area.
The verification of a measurement system is an essential part of system development. For this purpose, various guidelines can be used to evaluate and validate photogrammetric systems. However, these guidelines are only designed to validate systems that observe a static scene. Hence, these guidelines cannot validate measurement systems that observe dynamic scenes. In addition, reference data is not available for most systems, making verification significantly more difficult or not a practical solution. In this work, a simulation-based verification approach is presented. The presented approach allows the analysis of complex systems and the investigation of specific processing steps. The approach is based on a Monte Carlo simulation, which only requires the probability density distributions of the input data and synthetic reference data. For this purpose, the probability density distributions of the input data are determined by kernel density estimation to generate realistic input data. The application is a wind tunnel test, where aerodynamic and structural dynamic phenomena are observed at a wind turbine model. The measurement system consists of four high-speed cameras, which acquire the rotor blades' deformations. The objective of the simulation is to evaluate the complete process regarding the accuracy and precision of the measurement system. Experimental data can be used to estimate the quality of the simulation. It was shown that the simulation produces realistic results and that it is suitable for validating dynamic measurement systems. The simulation showed that the precision and accuracy of the system are highly dependent from the estimation of the self-motion. The achieved accuracy is still high and allows the detection of small-scale blade deformations.
Laima Catherine Alfonso-Orjuela, Yezid Alfonso Cancino-Gómez, Julio Alberto Perea- Sandoval
Small
and medium enterprises (SMEs) are firms that have a wide impact on the country’s
economy in Colombia and contribute 28% of GDP, so it is essential to achieve
the competitiveness of these organizations. The government has promoted plans
to adopt information and communications technologies (ICT) at SMEs to increase
their productivity and competitiveness. SMEs are organizations that lag behind
in technology adoption. Several investigations have been carried out to
characterize them, but no questions have been raised regarding the different
types of SMEs that can be found according to their ICT implementation. This
research aimed to determine the current usability and perception in the
implementation of ICT and subsequently classify organizations based on these
two factors. The results describe five types of SMEs: those that experience,
those that have been negligent, those that lag behind, those that hesitate, and
those that improvise. The data were collected in 2019, reflecting the state of
SMEs before the lockdown due to the SARS-CoV-2 virus outbreak.
We consider the motion of a magnetized satellite-gyrostat in a circular orbit due to the combined influence of uniform gravity and magnetic fields. Based on the Lagrangian equations, the necessary conditions for the existence of regular precessions are determined in which the axis of precession i\s perpendicular to the orbital plane. All possible regular precessions and permanent rotations are determined and classified. We show the usage of Lagrange equations taking Eulerian angles as generalized coordinates for determining the regular precessions is more effective and accurate than utilization of Euler-Poisson equations.
Production planning has an important role in the company's business processes. A company engaged in the manufacture of intermediate gear parts has a problem in optimizing its production system. The production planning system that occurs is still based on predictions from decision-makers. This study aims to optimize the production planning system to maximize the 15T intermediate gear spare parts' production capacity and the 30T intermediate gear spare parts. Optimization of production planning uses the fuzzy goal programming method to optimize objectives based on existing constraints such as working hours, profit tolerance values, and demand tolerance values. The results showed that the use of fuzzy goal programming was able to increase the production level by 2.765, with an increase in profit of 2.57%. Fuzzy goal programming implementation provides an optimal solution in increasing profits in accordance with company goals based on the constraints that occur.
Skuodis Šarūnas, Dirgėlienė Neringa, Medzvieckas Jurgis
Geogrids are widely used in civil engineering projects to reinforce road and railway structures. This paper presents research on the shearing strength of soil samples that have been reinforced with geogrids. The relationship between soil and geogrids is explored and evaluated by modeling the mechanical behavior of heterogeneous materials. For the purposes of this research, data obtained from tests of unreinforced sand samples with triaxial cells were compared with the data obtained from tests of reinforced sand samples. It was found that the shearing strength for reinforced samples was higher (from 9% to 49%) compared to unreinforced samples. Some damage to the geogrid was detected during the experiment, and for this reason, the same tests were numerically simulated for both unreinforced samples and samples reinforced with geogrids. Numerical simulations revealed the main reasons for damage to the geogrids during triaxial testing.
Engineering geology. Rock mechanics. Soil mechanics. Underground construction
Artificial general intelligence (AGI) progression metrics indicate AGI will occur within decades. No proof exists that AGI will benefit humans and not harm or eliminate humans. I propose a set of logically distinct conceptual components that are necessary and sufficient to 1) ensure various AGI scenarios will not harm humanity and 2) robustly align AGI and human values and goals. By systematically addressing pathways to malevolent AI we can induce the methods/axioms required to redress them. Distributed ledger technology (DLT, ‘blockchain’) is integral to this proposal, e.g. ‘smart contracts’ are necessary to address evolution of AI that will be too fast for human monitoring and intervention. The proposed axioms: 1) Access to technology by market license. 2) Transparent ethics embodied in DLT. 3) Morality encrypted via DLT. 4) Behavior control structure with values at roots. 5) Individual bar-code identification of critical components. 6) Configuration Item (from business continuity/disaster recovery planning). 7) Identity verification secured via DLT. 8) ‘Smart’ automated contracts based on DLT. 9) Decentralized applications - AI software modules encrypted via DLT. 10) Audit trail of component usage stored via DLT. 11) Social ostracism (denial of resources) augmented by DLT petitions. 12) Game theory and mechanism design.
We report an experimental study on the piezophotonic effect of gold and lead zirconate titanate (PbZrTiO3) nanoparticles (NPs) and also their core-shell nanostructures prepared by the laser ablation in liquid method. To obtain these NPs and composite materials, the targets were immersed in deionized water and a polymeric solution of polyvinyl pyrrolidone (PVP) under Nd:YAG laser pulses irradiation. Linear and nonlinear properties of these NPs were studied by optical spectroscopy and the Z-scan technique. Furthermore, tunable nonlinear properties of the NPs were measured under an external electric field under illumination to investigate the piezophotonic effect. Our results show that, at the interface of PZT and Au, due to the Schottky barrier, we have electron/hole recombination prevention, which leads to efficient enhancement in the nonlinear properties.