Search Results (5,022)

The vacuum drying of cellulose-based insulation is an essential step in the transformer manufacturing process, typically consisting of both heat and vacuum application. The moisture inside cellulose insulation during this process is transferred by various transport mechanisms, some of which are affected by the insulation’s temperature. Moreover, the conditions within the vacuum chamber are generally transient and highly dynamic, depending on the employed process control strategy, and may include various phenomena, such as gas expansion during pump-down and radiative heat transfer. From a modelling perspective, these factors can significantly impact the drying rate by altering the boundary conditions of heat and mass transport equations. To account for such effects, a model that considers the process at both the scale of cellulose insulation and the scale of the vacuum chamber is presented. A simplified drying system with two-point process control is introduced to simulate multiple cases. The results highlight the sensitivity of drying behaviour to both the model parameters and the selected control strategy. A comparison with existing Fickian diffusion models indicates that the proposed model, when properly calibrated, can reliably reproduce drying dynamics and thus provide a powerful tool for optimizing vacuum drying procedures. Full article

Recent advancements in emerging technologies such as IoT and AI have driven digital innovation, while also accelerating the sophistication of cyberattacks and expanding the attack surface. In particular, inter-state cyber warfare, sophisticated ransomware threats, and insider-led personal data breaches have emerged as significant new security risks. In response, this study proposes a Privacy-Aware Integrated Log System model developed to mitigate diverse security threats. By analyzing logs generated from personal information processing systems and security systems, integrated scenarios were derived. These scenarios are designed to defend against various threats, including insider attempts to leak personal data and the evasion of security systems, enabling scenario-based contextual analysis that goes beyond simple event-driven detection. Furthermore, the Analytic Hierarchy Process (AHP) was applied to quantitatively assess the relative importance of each scenario, demonstrating the model’s practical applicability. This approach supports early identification and effective response to personal data breaches, particularly when time and resources are limited by focusing on the top-ranked scenarios based on relative importance. Therefore, this study is significant in that it goes beyond fragmented log analysis to establish a privacy-oriented integrated log system from a holistic perspective, and it further validates its operational efficiency in field applications by conducting an AHP-based relative importance evaluation. Full article

Spacecraft and satellites are equipped with cryogenic storage systems to maintain instruments and engines at optimal operating temperatures. However, in cryogenic storage tanks, the steep temperature gradient along the pipeline (arising from sections inside and outside the tank) may induce instability in stored gases such as helium or hydrogen, leading to large-amplitude, self-excited thermoacoustic oscillations, known as Taconis oscillations. Taconis oscillations not only cause structural damage to pipelines, jeopardizing the safety of the cryogenic storage system, but also produce significant heat leakage and boil-off losses of cryogens. This study employs computational fluid dynamics (CFD) to simulate Taconis oscillations within a U-shaped cryogenic helium pipeline. The flow dynamics and acoustic field characteristics of the cryogenic helium pipeline are first analyzed. Fast Fourier transform and wavelet transform are employed to characterize the Taconis oscillations. A subsequent parametric study investigates the influence of the location and magnitude of temperature gradients on the dynamic behavior of Taconis oscillations. Simulation results reveal that the onset temperature gradient is at a minimum when the temperature gradient is applied at one-quarter of the cryogenic pipeline. To prevent the occurrence of Taconis oscillations, the transition between the warm and cold sections should be away from one-quarter of the cryogenic helium pipe. Moreover, increasing the temperature gradient leads to the emergence of multiple oscillation modes and an upward shift in their natural frequencies. This research gives deeper insights into the dynamics of thermally induced thermoacoustic oscillations in cryogenic pipelines, providing guidelines for improving the efficiency and safety of cryogenic storage systems in aerospace engineering. Full article

Coccidioides species are thermally dimorphic fungal pathogens that cause coccidioidomycosis (Valley Fever) primarily in North and South America. Coccidioides grow as hyphae that differentiate into arthroconidia, which can be aerosolized upon soil disturbance, and inhaled by the mammalian host to cause pulmonary infections with occasional dissemination to other organs. In the context of mouse models, current methods of infection include intranasal, intravenous, and intraperitoneal delivery of the arthroconidia into mice. To explore an aerosol route of infection, we compared the intranasal method with aerosolization using the Glass-Col Inhalation Exposure System (IES). Infection with a dose of 2 × 10⁶ CFU/mL, nebulized in 5 mL of PBS, but not in water, was able to infect mice, albeit inconsistently, compared to intranasal challenge. Arthroconidia were detected inside the IES after the nebulization and decontamination cycles. These studies highlight some of the challenges with aerosolization of Coccidioides arthroconidia and serve as a reminder about biosafety considerations for use of the IES to aerosolize pathogens. Full article

Many buildings in Southern European countries are equipped with both gas boilers and air source heat pumps. The present work concerns an experimental evaluation of indoor comfort in an apartment within a residential building, comparing a gas boiler with cast-iron radiators to an air-to-air heat pump. The comfort conditions inside the apartment are assessed at set-point temperatures of 20 °C and 21 °C and with different water supply temperatures from the gas boiler. Energy consumption data for both heating systems are recorded during the tests. The measurements inside the apartment are conducted using inexpensive, widely accessible sensors and Arduino-like microcontrollers, calibrated before use. As a result, comfort indices for the heat pump are between those for the gas boiler at 20 °C and 21 °C. Additionally, to understand the impact of occupancy, an analysis of local discomfort and air quality was conducted by measuring CO₂ levels, which rose significantly without air exchange. Lastly, the experimental results are compared with previous dynamic and Computational Fluid Dynamics (CFD) analyses, showing the limit of the computational approach. Indeed, the comfort indices derived from the experimental study are superior to those obtained from dynamic simulations and CFD. Full article

This study evaluated the qualitative and quantitative performance of lettuce (cv. Romana) grown using different cultivation systems under Mediterranean greenhouse conditions equipped with photoluminescent glass panels. Five systems were compared: outdoor soil (PSO), indoor soil (PSI), aeroponic (A), hydroponic with inorganic nutrients (HSN), and hydroponic with organic nutrients (HSO). Morphological, physiological, and quality parameters were measured alongside solar irradiance and extended PAR. The results showed that aeroponics significantly outperformed other systems in fresh weight (52.7 g), photosynthetic pigments, and carotenoids, while HSO showed the lowest yield and quality. Although PSO had the highest antioxidant activity and phenolic content, it exhibited poor yield due to lower water use efficiency and light-induced stress. The PCA analysis highlighted distinct groupings among systems, with A linked to yield and pigment concentration, and PSO associated with antioxidant traits. Despite a 44.8% reduction in solar radiation inside the greenhouse, soilless systems—especially aeroponics—proved effective for maintaining high productivity and quality. These findings support the integration of soilless systems and photoluminescent technologies as sustainable strategies for high-efficiency lettuce production in controlled environments. Full article

The present reported work deals with the preparation of an energy-efficient smart window based on liquid crystal (LC) using a polymer-dispersed liquid crystal (PDLC) technique. The smart window was prepared using an LC–polymer composite by mixing photopolymer NOA-71 into nematic liquid crystal (NLC) 4-cyano-4’-pentylbiphenyl (5CB). The liquid crystal cell was prepared, the LC–polymer composite was filled inside the cell, and voltage was applied after the exposure of ultraviolet (UV) light. Textural analysis was carried out, and microscope images were taken out with the variation in voltage. Optical measurements were also performed for the smart window based on the PDLC system. Threshold voltage and saturation voltages were measured to carry out the operating voltage analysis. Transmittance was measured as a function of wavelength at different voltages. An absorbance study was also performed, varying the voltage and wavelength. The change in the power of the laser beam passing through the prepared smart window as a function of voltage was also investigated. The working of a prepared smart window using liquid crystal and a photopolymer composite is also demonstrated in opaque and transparent states in the absence and presence of voltage. The output of the present investigation into a PDLC-based smart window can be useful in the applications of adaptive or light shutter devices and in aerospace technology, as it shows the dual nature of opaque and transparent states in the absence and presence of electric field. Full article

Measuring-while-drilling (MWD) techniques have great potential for use in geotechnical engineering research. This study first addresses the current use of MWD, which consists of recording data using sensors in a drilling machine operating on site. It then addresses the currently unsolved problems of quality control in drilled piles and assessments of their interaction with the soil under load. Next, an original method of drilling displacement piles using a special EGP auger (Electro-Geo-Probe) is presented. The innovation of this new drilling system lies in the placement of the sensors inside the EGP auger in the soil. These innovative sensors form an integrated measurement system, enabling improved real-time control during pile drilling. The most original idea is the use of a Cone Penetration Test (CPT) probe that can be periodically and remotely inserted at a specific depth below the pile base being drilled. This new MWD-EGP system with cutting-edge sensors to monitor the soil’s impact on piles during drilling revolutionizes pile drilling quality control. Furthermore, implementing this in-auger sensor system is a step towards the development of digital drilling rigs, which will provide better pile quality thanks to solutions based on the results of real-time, on-site soil testing. Finally, examples of measurements taken with the new sensor-equipped auger and a preliminary interpretation of the results in non-cohesive soils are presented. The obtained data confirm the usefulness of the new drilling system for improving the quality of piles and advancing research in geotechnical engineering. Full article

Apolipoprotein A (ApoA) proteins, ApoA-I, ApoA-II, ApoA-IV, and ApoA-V, play critical roles in lipid metabolism, neuroinflammation, and blood–brain barrier integrity, making them pivotal in neurological diseases such as Alzheimer’s disease (AD), stroke, Parkinson’s disease (PD), and multiple sclerosis (MS). This review synthesizes current evidence on their structural and functional contributions to neuroprotection, highlighting their dual roles as biomarkers and therapeutic targets. ApoA-I, the most extensively studied, exhibits anti-inflammatory, antioxidant, and amyloid-clearing properties, with reduced levels associated with AD progression and cognitive decline. ApoA-II modulates HDL metabolism and stroke risk, while ApoA-IV influences neuroinflammation and amyloid processing. ApoA-V, although less explored, is implicated in stroke susceptibility through its regulation of triglycerides. Genetic polymorphisms (e.g., APOA1 rs670, APOA5 rs662799) further complicate disease risk, showing population-specific associations with stroke and neurodegeneration. Therapeutic strategies targeting ApoA proteins, including reconstituted HDL, mimetic peptides, and gene-based approaches, show promise in preclinical models but face translational challenges in human trials. Clinical trials, such as those with CSL112, highlight the need for neuro-specific optimization. Further research should prioritize human-relevant models, advanced neuroimaging techniques, and functional assays to elucidate ApoA mechanisms inside the central nervous system. The integration of genetic, lipidomic, and clinical data offers potential for enhancing precision medicine in neurological illnesses by facilitating the generation of ApoA-targeted treatments and bridging current deficiencies in disease comprehension and therapy. Full article

Lithium-rich manganese-based oxides (LMR) are promising next-generation cathode materials due to their high capacity and low cost, but safety remains a critical bottleneck restricting the practical application of high-energy-density cathodes. However, the safety level of LMR batteries and the thermal failure mechanism of the cathode are still poorly understood, especially when compared with traditional high-energy nickel-rich (Ni-rich) cathodes. Here, we investigate the LMR cell’s thermal runaway behavior and the thermal failure mechanism of the cathode. Compared to a Ni-rich cell, Accelerating Rate Calorimetry (ARC) shows the LMR pouch cell exhibits a 62.7 °C higher thermal runaway trigger temperature (T2) and 270.3 °C lower maximum temperature (T3). These results indicate that the cell utilizing a higher-energy-density LMR cathode presents significantly lower thermal runaway risks and hazards. The results of differential scanning calorimetry–thermogravimetry–mass spectrometry (DSC-TG-MS) and in situ heating X-ray diffraction (XRD) indicate that the LMR cathode has superior thermal stability compared with the Ni-rich cathode, with cathode oxygen released at higher temperatures and lower rates, which is beneficial for delaying and mitigating the exothermic reaction inside the battery. This study demonstrates that simultaneously enhancing cathode energy density and battery safety is achievable, and these findings provide theoretical guidance for the design of next-generation high-energy and high-safety battery systems. Full article

Shared energy storage (SES) systems, operating alongside microgrid clusters, can effectively mitigate power fluctuations and reduce the operational costs of independently constructed energy storage systems. Consequently, capacity allocation planning for SES in microgrid clusters has emerged as a crucial technology for achieving the system’s economical and efficient operation. This paper presents a two-layer optimal allocation model utilizing the Alternating Direction Method of Multipliers (ADMMs) to characterize system operation precisely. By establishing a refined mathematical model of a microgrid cluster with SES and analyzing the energy flow interaction mechanisms inside the cluster, along with the configuration scheme for SES capacity. The upper layer optimization of the model minimizes operational and maintenance investment costs associated with designing the capacity of SES, while the lower layer model optimizes the operation scheduling with the goal of the lowest operation cost. To illustrate the efficacy and benefits of the proposed method, case studies are conducted in different scenarios comparing the proposed method with the conventional method to analyze the power distribution features of the microgrid and the allocation planning of shared energy storage capacity. Full article

This paper presents a novel design strategy for outlier-robust, three-element non-uniform linear array (NULA) configurations optimized for multiple-input multiple-output (MIMO) radar systems aimed at target direction of arrival (DoA) estimation. The occurrence of outliers, i.e., ambiguous estimates, is a well-known issue in DoA estimation based on the maximum likelihood (ML), which is caused by the local maxima of the likelihood function. Specifically, we study how the positioning of both transmitters and receivers affects both presence of outliers and accuracy of ML DoA estimation. By leveraging a theoretical prediction of the DoA mean squared error (MSE), we propose a design strategy to jointly optimize the positions of NULA array of three transmitting and receiving elements, only inside a subspace which guarantees that the outlier probability remains below a specified threshold. Compared to NULA configurations with a single transmitter, the proposed designs achieve superior estimation accuracy due to two key factors: improved asymptotic performance resulting from a narrower mainlobe, and enhanced robustness against outliers due to reduced sidelobes. Furthermore, the proposed approach is well-suited for practical implementation in low-cost radars using only 3 × 3 or 2 × 3 MIMO configurations, as it also incorporates practical design constraints such as minimum inter-element spacing to account for the physical dimensions of the antennas, and tolerance in the installation accuracy. Full article

The thermal insulation performance of liquid hydrogen (LH₂) storage tanks is critical for long-distance transportation. The active cooled shield (ACS) technologies, such as the liquid nitrogen cooled shield (LNCS) and the vapor hydrogen cooled shield (VHVCS) are important thermal insulation methods. Many researchers installed the VHVCS inside the multilayer insulation (MLI) and obtained the optimal position. However, the MLI layer is often thinner than the vacuum interlayer between the inner and outer tanks, and there is a large vacuum interlayer between the outermost side of MLI and the inner wall of the outer tank. It is unknown whether the insulation performance can be improved if we install ACS in the mentioned vacuum interlayer and separate a portion of the MLI to be installed on the outer surface of ACS. In this configuration, the number of inner MLI (IMLI) layers and the ACS position are interdependent, a coupling that has not been thoroughly investigated. Therefore, thermodynamic models for MLI, MLI-LNCS, and MLI-VHVCS schemes were developed based on the Layer-by-Layer method. By applying Robin boundary conditions, the temperature distribution and heat leakage of the MLI scheme were predicted. Considering the coupled effects of IMLI layer count and ACS position, a co-optimization strategy was adopted, based on an alternating iterative search algorithm. The results indicate that for the MLI-LNCS scheme, the optimal number of IMLI layers and LNCS position are 36 layers and 49%, respectively. For the MLI-VHVCS scheme, the optimal values are 21 layers and 39%, respectively. Compared to conventional MLI, the MLI-LNCS scheme achieves an 88.09% reduction in heat leakage. However, this improvement involves increased system complexity and higher operational costs from LN₂ circulation. In contrast, the MLI-VHVCS scheme achieves a 62.74% reduction in heat leakage, demonstrating that using sensible heat from cryogenic vapor can significantly improve the thermal insulation performance of LH₂ storage tanks. The work of this paper provides a reference for the design and optimization of the insulation scheme of LH₂ storage tanks. Full article

In this paper, time series of length T are seen as frequency distributions. Each distribution is defined with respect to a statistical variable having T observed values. A methodological system based on Gini’s approach is put forward, so the statistical model through which time series are handled is a frequency distribution studied inside a linear system. In addition to the starting frequency distributions that are observed, other frequency distributions are treated. Thus, marginal distributions based on the notion of proportionality are introduced together with joint distributions. Both distributions are statistical models. A fundamental invariance property related to marginal distributions is made explicit in this research work, so one can focus on collections of marginal frequency distributions, identifying multiple frequency distributions. For this reason, the latter is studied via a tensor. As frequency distributions are practical realizations of nonparametric probability distributions over $\mathbb{R}$, one passes from frequency distributions to discrete random variables. In this paper, a mathematical model that generates time series is put forward. It is a stochastic process based on subjective previsions of random variables. A subdivision of the exchangeability of variables of a statistical nature is shown, so a reinterpretation of principal component analysis that is based on the notion of proportionality also characterizes this research work. Full article

Background: Emerging parameters, such as the spino-pelvic unit and the combined sagittal index (CSI), are gaining importance in evaluating and optimizing implant positioning in total hip arthroplasty (THA). Our institution adopts the “femur first” technique to achieve the desired combined anteversion (CA). The purpose of this study is to evaluate the role of the ‘femur first’ technique and spinopelvic characteristics in achieving the CSI_standing ‘safe zone’ in primary THA. Methods: Consecutive patients undergoing primary THA were included in the present retrospective study. All patients underwent radiographic assessments in the standing position with the EOS 2D/3D radiography system. Results: Forty patients (40 hips) were enrolled. Of these, 34 patients fell inside the CSI_standing “safe zone” (205–245°). When considering the restricted CSI_standing “safe zone” for patients at high risk for adverse spinopelvic characteristics (215–245°), only 16 patients fell inside the range. We demonstrated a positive linear correlation between CSI_standing and CA (p < 0.0001). Pelvic tilt (PT) showed a positive correlation both in standing and relaxed sitting positions, (p < 0.001). Sacral slope (SS) showed a significant positive correlation in the relaxed sitting (p = 0.003) position but not in the standing position (p = 0.34). The correlation analysis between CSI_{relaxed-sitting} and ΔSS showed a positive correlation (p = 0.003). Conclusions: The “femur first” technique is able to achieve the CSI “safe zone” in most patients; however, it seems insufficient in those with adverse spinopelvic characteristics, who are at higher risk of dislocation. Moreover, the CA, the position of the pelvis in space (PT), and its mobility (ΔSS) greatly influence the CSI “safe zone” in patients undergoing primary THA. Full article