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Compared with solid solution (SS) Hf0.5Zr0.5O2, HfO2–ZrO2 superlattice (SL) ferroelectric films exhibit enhanced endurance and reduced leakage. However, so far, the underlying physical mechanism is still missing. In this work, first-principle calculations reveal that the superior reliability arises from the precise control in the spatial profile of oxygen vacancy with the stacked structure in SL in which oxygen vacancies (Vo) exhibit different formation energies and different energy profiles in Zr- and Hf-layers. However, Vo have the tendency to migrate and its suppression become critical to maintain the superiority of SL. A low annealing temperature is, therefore, suggested and validated with our fabricated SL- and SS-ferroelectric films with different annealing temperatures. This understanding can pave ways for the optimization in SL ferroelectric films. [ABSTRACT FROM AUTHOR]

This study aimed to determine various thermoelectric properties, including the dimensionless figure of merit (zT0), resistivity (ρTE), thermal conductivity (κTE), and Seebeck coefficient (S), using a combination of 3ω and time-domain impedance spectroscopy (TDIS) methods for a thermoelectric module at absolute temperature (T0). The effective dimensionless figure of merit (zT0,eff), influenced by heat leakage through attached lead wires, was quantitatively and qualitatively assessed based on the TDIS method. The results demonstrated that zT0,eff/zT0 can be expressed as the ratio between the thermal conductance of the attached thermoelectric element and the lead wire. Thus, by considering heat leakage through the lead wire, the TDIS method can estimate not only zT0 and ρTE but also κTE and S after measuring the lead wire's thermal conductivity using the 3ω method. The study utilized a commercial Π-shaped bismuth-telluride-based thermoelectric module and derived representative values for its elements. zT0, ρTE, κTE, and |S| at 300 K were 0.871, 10.15 μΩ m, 1.71 W/mK, and 224 μV/K, respectively, consistent with previous reports on representative bismuth-telluride-based materials. In conclusion, the combination of the 3ω and TDIS methods is useful for determining all thermoelectric properties, considering heat leakage through attached lead wires. [ABSTRACT FROM AUTHOR]

Recently, researchers have demonstrated, both theoretically and experimentally, that low-dimensional version of conventional leaky waves, known as "flatland leaky waves" (FLWs). FLWs can be supported by planar junctions of metasurfaces and are completely confined to a plane. Here, we design a structure that places an equivalent reactance surface near the transmission line to excite the FLWs. By properly designing the geometry of the unit cell, conditions can be created for faster surface waves (SWs) to excite slower SWs on the surface, resulting in the desired form of two-dimensional (2D) leaky-wave radiation. A sample was fabricated and measured, and both the simulation results and the experimental results yielded the desired results. Finally, we design the equivalent impedance surface model on which we can also observe the 2D FLWs. Our research not only deepens the understanding of the phenomenon of FLWs but also brings the application of equivalent reactance surfaces in the field of electromagnetic phenomena research to a higher level. [ABSTRACT FROM AUTHOR]

In this study, the dispersion and explosion of liquid hydrogen (LH 2) in leakage accidents are investigated using the Flame Accelerator Simulator (FLACS) code. The study focus was a liquid hydrogen research facility in Gimhae, South Korea. Simulations were conducted under various conditions by varying the mass flow rates (0.61 and 0.3 kg/s), directions (lateral in areas with minimal structures, lateral towards a tube trailer truck, and downward), and durations (90 and 180 s) of leakage. The results indicated that higher leakage mass flow rates produce a larger flammable cloud volume (FCV), resulting in higher maximum overpressures than that caused by lower flow rates. Downward leakage generally resulted in a larger FCV and higher overpressure than lateral leakage. The explosion characteristics were also influenced by geometry of LH 2 facility, including the presence of structures in the leakage path. Contrastingly, leakage duration had a minimal effect on the maximum overpressure because an increased duration causes a greater dilution of hydrogen, only slightly expanding the FCV. According to the overpressure–impulse diagram, higher leakage flow rates cause severe health risks, approaching thresholds for lung rupture and 100% fatality. Contrary to the minor damages caused by lower leakage flow rates. High flow rates, particularly with downward leaks, can cause significant structural damage in brick buildings, potentially leading to partial demolition. • Higher leakage mass flow rates result in larger flammable cloud volumes and increased maximum overpressures. • Downward hydrogen leaks lead to larger flammable clouds and higher overpressures than lateral leaks. • Facility geometry and structures significantly affect explosion overpressure magnitude and distribution. • Leakage duration has a minimal effect on maximum overpressure due to hydrogen dilution during leakage. [ABSTRACT FROM AUTHOR]

Introduction: Nasal high flow (NHF) is a popular technique to provide support in respiratory failure in different conditions. Recently published bench studies have hypothesized that airway pressure can be increased by using different cannula sizes and corresponding prongs resulting in a range of prong-nare ratios. We conducted this study to verify these experimental findings in clinical practice. Methods: We characterized prong size and flow rate dependent changes in ventilation parameters and changes in hypercapnia in an interventional clinical setting. Outcome parameters included changes in mean airway pressure, tidal volume (TV), respiratory rate (RR), minute volume (MV) and decrease in pCO2. The ventilatory parameters were determined at 20, 30, 40 and 50 l/min with 3 different prong sizes. 20 and 40 l/min and the 3 different prong sizes were used to document the changes in pCO2. Results: In this study we demonstrate changes in ventilation with increasing flow rates of NHF. A significant increase in mean airway pressure was seen with every 10 l/min increase in flow rate. Respiratory rate and minute volume (using large prongs) changed significantly with larger increases in flow rate, while tidal volume was not significantly altered. When the flow rate was increased by 20 l/min (i.e. from 20 l/min to 40 l/min) capillary pCO2 decreased significantly. None of the measured values were significantly altered by the prong size used. Conclusion: In summary, we presented strong indications that different prong sizes have no influence on essential respiratory parameters or the elimination of pCO2 when using NHF in COPD patients. [ABSTRACT FROM AUTHOR]

ABSTRACT This paper proposes a flyback converter with a new passive lossless snubber. It eliminates the power dissipation of the traditional RCD snubber, while providing protection against MOS breakdown from energy stored in the power‐transformer leakage. This energy is used to power the power chip, which simplifies the design of the transformer. Meanwhile, an optimal design method for high power density planar transformers is presented. Applying the principle of flux cancellation, a matrix transformer that originally needed an independent magnetic core was integrated into a single magnetic core to reduce the volume of the core. This method effectively reduces the printed circuit board (PCB) layer number of the planar transformer and increases the possibility of the application of the planar transformer in the flyback converter. The detailed operation principle and design considerations are presented. Finally, a multi‐output flyback converter with a frequency of 100 kHz is designed to verify the practical performance of the structure. [ABSTRACT FROM AUTHOR]

The mass flow rate of hydrogen leakage directly affects hydrogen diffusion and concentration distribution. In this paper, a test platform was constructed to measure mass flow rates during hydrogen leakage in the supply pipelines of the on-board hydrogen system. Hydrogen leakage tests were conducted under two different conditions. Mass flow rates were measured for tube fittings with various loosening angles and hydrogen supply pressures. The data were then fitted to extrapolate mass flow rates of hydrogen leakage beyond the tested conditions. Additionally, mass flow rates were measured for hydrogen supply pipelines with small holes of different shapes and sizes. The effects of pipeline size, hydrogen supply pressure, hole shape, and size on the hydrogen leakage mass flow rate were analyzed. Hydrogen leakage flow coefficients were corrected, and the accuracy of three calculation methods for hydrogen leakage flow was compared and analyzed based on the test results. The results provide a foundation for future numerical simulation models of hydrogen leakage diffusion. • A hydrogen leakage test platform for hydrogen supply pipeline has been set up. • Hydrogen flow rates of tube fittings with different loosening angles are measured. • Hydrogen flow rates of leakage holes with different shapes and sizes are measured. • Three flow calculation methods are comparatively analyzed based on test data. [ABSTRACT FROM AUTHOR]

The volumetric efficiency of the hydrogen circulation pump (HCP) is mainly affected by the amount of leakage in working clearances. Studying the leakage characteristics of working clearances is of great significance for optimizing the performance of the HCP. Therefore, this paper developed a three-blade elliptical conjugate rotor HCP, and compared the results of experiments and simulations for different working conditions. On this basis, the flow rate, pressure, and internal flow field changes of radial clearance models and axial clearance models with four different scales of 0.1mm, 0.14mm, 0.18mm, and 0.22 mm were studied. The results indicate that: under four different pressure ratios and rotational speeds, the simulation results using the overlapping grid method showed a maximum difference of 4.17% compared to the experimental results, verifying the reliability of the simulation calculation method; the average flow rate of the HCP is linearly inversely proportional to both the radial clearance and the axial clearance, with a decrease rate of 11.6 Nm3/h and 5.8 Nm3/h as the clearance size increases by 0.04 mm; the radial clearance leakage of the same size is higher than the axial clearance, the leakage value in the radial clearance between the rotors is higher than that between the rotor and the pump casing, and the internal leakage of axial clearance is not evenly distributed, with higher leakage value in the middle area than that in the left and right areas. [ABSTRACT FROM AUTHOR]

Smart sensor technologies to monitor temperature and moisture conditions in building components can be used to give automatic warnings for abnormal high levels of moisture. Flat compact roofs are of particular interest in this context, especially due to their vulnerability to rain leakages through the roofing membrane. Installing moisture sensors in such roofs measuring relative humidity (RH) and free water may give an early warning of rain leakages or condensation owing to air leakages from indoors before damage occurs. One challenge is, however, that normal moisture redistribution in the insulation layer over the season or a day may give very high levels of RH in the top or bottom part of the insulation. A sensor system must be able to distinguish between these normal RH levels and leakage events. Together with a sensor technology and control system producer, a semi-quantitative system that defines typical or normal RH levels in the insulation layer of the roof during the year has been developed. To investigate the applicability of such a system, measurements from the compact roofs of two pilot buildings located in Norway have been analysed. The objective has been to identify connections between measured data, occurring climate conditions and seasonal variations. Results may be used to further develop and improve the algorithms of the leakage warning system. [ABSTRACT FROM AUTHOR]

Plasma‐based technologies offer environmentally friendly means of effective water purification. Here, we present a discharge system with He + 1% O2 ${{\rm{O}}}_{2}$. Tunable amounts of H2 ${{\rm{H}}}_{2}$ were introduced to control the yield of reactive species. Detailed exploration of the system provides a deeper understanding of some of the fundamental chemical kinetics related to plasma‐based wastewater treatment. A global model was used to investigate the effect of H2 ${{\rm{H}}}_{2}$ additions on the yield of some important reactive species for advanced oxidation treatment of wastewater. Humidity leakage was considered to simulate the effect of humidified environments. The pathway analysis module provides deeper insight into chemical kinetics. It was concluded that H2 ${{\rm{H}}}_{2}$ additives can be used in tailoring plasma yield for water treatment applications. [ABSTRACT FROM AUTHOR]

Intradiscal injection is required to deliver therapeutic agents to the intervertebral disc (IVD) nucleus pulposus (NP). However, injectate leakage following needle retraction may result in decreased treatment efficacy and adverse side effects. While enzymatic digestion is a common research approach for simulating degeneration in healthy animal IVDs, contributions to the leakage phenomenon are unknown. In this study, bovine caudal discs were treated with injection into the NP of either a tris buffer control, collagenase (to primarily target collagen), or trypsin (to primarily target proteoglycans) and then injected with fluorescent saline using a through-puncture defect protocol. Pressure–volume records during injection were used to determine volume and pressure at leakage. Discs were then frozen, transected, and photographed to visualize injectate dispersion. Collagenase treatment resulted in a large increase in injectate dispersion, along with a decrease in injection pressure relative to control. Trypsin treatment resulted in a moderate increase in dispersion, with no associated effect on pressure. This study concludes that care should be taken when employing enzymatic digestion to simulate IVD degeneration, as NP tissue disruption may affect both retention and dispersion of subsequent therapeutic injections. [ABSTRACT FROM AUTHOR]

Essential oils are promising antimicrobial agents against various bacteria. The aim of the study was to examine anti- Acinetobacter baumannii activity of nine essential oils and to elucidate essential oil mechanisms of action against this. In total, 8 out of 9 examined different essential oils exhibited activity against multidrug-resistant (MDR) A. baumannii isolates. The best anti- A. baumannii activity expressed Thymus serpyllum, Satureja hortensis and Oreganum majorana essential oil (MBC 1.29 to 2.58 µg mL−1), while essential oils of Menta x piperita, Hyssopus officinalis, Foeniculum vulgare and Artemisia dracunculus expressed the same effect in higher concentrations (1.80 to 3.80 µg mL−1). The effect of Juniperus sabina, Juniperus sibirica and S. hortensis essential oils against A. baumannii is for the first time reported here. The mechanisms of Myrtus communis, Eucalyptus camaldulensis, S. hortensis and T. serpyllum essential oils were further examined. The essential oil treatments led to concentration dependent leakage of biomolecules form the cells, causing an increase in the concentrations of lipids, carbohydrates, and proteins in the suspensions. Microstructural observations confirmed the essential oil effect on cell membranes and disruption the membrane integrity, with obvious leakage of intercellular substance, collapsed cells with perforations, debris presence and autoaggregated cells. The subinhibitory concentrations of oils did not obviously changed protein patterns determined by SDS-PAGE. These results indicate that the essential oils, particularly T. serpyllum, S. hortensis, M. communis and E. camaldulensis express its anti- A. baumannii activity via membrane disruption and increased membrane permeability, representing very promising alternative antibacterial agents against MDR wound isolates. [Display omitted] • Essential oils (EO) exhibit promising antimicrobial activity against MDR A.baumannii. • M. communis, E. camaldulensis, S. hortensis, T. serpyllum EOs disrupt membranes. • EOs increase cell autoaggregation, membrane permeability and biomolecules leakage. • Microstructural observations confirmed cell collapse, perforations, debris presence. • Subinhibitory concentrations of oils did not significantly alter protein patterns. [ABSTRACT FROM AUTHOR]

This work is focused on the testing of a new 68Ge/68Ga radionuclide generator based on cerium dioxide in polyacrylonitrile beads. During an 18-month period, parameters of elution were monitored, and basic radiolabelling studies were carried out. As current commercial solutions deal with high elution volume and low long-term stability, the constructed system offers several improvements. The composite sorbent provides uniformity of active component dispersion and high capacity for 68Ge. It enables minimal elution volume without fractionation (up to 1.8 mL) and stability of 68Ge breakthrough (under 0.001%) after initial period of wash-out and low cerium leakage (under 5 ppm). [ABSTRACT FROM AUTHOR]

Severe complications following hepato-pancreato-biliary surgery are frequently due to leakage of anastomoses. Local intraoperative and systematic measures can reduce the incidence of leaks and leak-related sequelae. The early identification of leak-related sequelae, such as hemorrhage is pivotal to reduce the mortality risk. Therefore, perioperative risk stratification incorporating surgical and patient risk factors is crucial. The management of anastomotic leaks is complex and an interdisciplinary treatment is therefore recommended. The treatment depends on the institutional expertise, localization, characteristic features of the anastomosis and the onset of insufficiency. This article describes the different concepts of the diagnostics, prevention, consequences and management of anastomotic leakage in hepato-pancreato-biliary surgery in more detail. [ABSTRACT FROM AUTHOR]

One of the most severe peel physiological disorders of orange fruits is Stem End Rind Breakdown (SERB), a severe postharvest physiological disorder. We expected foliar Ca and K application to reduce orange SERB by modifying several peel biochemical and physical characteristics. Therefore, one experiment (2018–2020) was designed in complete randomized blocks in four treatments with three replicates. Experimental treatments included foliar spray of (1) K nitrate; (2) Ca nitrate; (3) Ca, and K nitrate separately, with a time interval (Ca + K; combination of treatments 1 and 2); (4) control. The effects of treatments were evaluated on several parameters underlying fruit peel quality at harvest and intensity of SERB damage after 12 wk of fruit storage at 5 ◦C and 85% RH. The results showed that K-treated fruits had higher TSS and TSS/TA than other fruits. Also, the Ca treatments (including Ca and Ca + K treatments) increased Ca content in fruit peels and significantly decreased SERB damage and weight loss by 70% and 30%, respectively. In addition, Thomson orange peel obtained from Ca-treated trees (including Ca and Ca + K treatments) displayed elevated levels of pectin than other fruits. In contrast, the peels of fruits picked from trees sprayed with Ca, especially those treated with Ca + K, exhibited lower levels of total phenolic, antioxidant, and electrolyte leakage than other fruits. This study suggests that foliar application of Ca(NO3)2 and KNO3 during the fruit growth cycle while improving the internal quality of the fruit is an effective agronomical strategy that prolongs Thomson orange shelf life. [ABSTRACT FROM AUTHOR]

The physical design and implementation of an LTCC on–off microswitch device is demonstrated. One model was used to describe microchannel fluidic behavior, especially those with rectangular cross-section, routinely used in microfluidic devices. Another model to describe PDMS microbridge deformation was applied, allowing for estimating the elastic stiffness of several manufactured membranes. From this approach, microswitch design was conducted regarding the simulation results associated with both models, aiming at miniaturization. Applying LTCC-PDMS fabrication methodology, the fluidic devices were manufactured as established by theoretical design and an experimental setup was proposed in order to evaluate system performance. Experimental investigations indicate that a weight of 120 g was necessary to reduce the water flow rate of the normally open LTCC-PDMS microswitch from 0.42 mL/min to 50 μL/min when submitted to a controllable pressure-driven system. The leakage observed when testing the fabricated microswitches regards the rough way in which the PDMS membrane was attached to the LTCC body. However, experimental results suggest that the novel microswitch can operate satisfactorily regarding micro total analysis applications. [ABSTRACT FROM AUTHOR]

Water seepage in tunnel lining cracks considerably influences the structural safety of a tunnel. In this study, chitosan was introduced in the enzyme-induced carbonate precipitation (EICP) to repair the cracks in in-service tunnel linings. The influence of chitosan incorporation on the Ca2+ precipitation ratio during EICP was analyzed by aqueous solution experiments, and the optimal content of added chitosan was obtained. Moreover, in terms of specimen scale and field tests, the determination of permeability characteristics, and mass loss, scanning electron microscopy and ground penetrating radar technology were used to analyze the changes in permeability coefficient and mass loss of cracked concrete repaired by chitosan-combined EICP under normal temperature (25°C±2°C) and freeze–thaw (FT) cycling conditions. The effect, feasibility, and action mechanism of chitosan-combined EICP for tunnel crack repair in extreme environments were explored. The results showed that the incorporation of an appropriate amount of chitosan in traditional EICP could accelerate Ca2+ precipitation, provide nucleation sites for the precipitation of CaCO3 , promote the existence of the deposited CaCO3 crystals in the form of calcite with higher strength, and reduce mass loss in extreme circumstances. The combination of hydrogel and CaCO3 makes the impermeable layer more compact and reduces the permeability coefficient of repair concrete. The permeability coefficient descends exponentially with the decrease of mass loss under FT conditions. Chitosan-combined EICP represents an environmentally friendly and feasible method for crack repair in in-service tunnel linings. [ABSTRACT FROM AUTHOR]

Unlike the hydrodynamic model used in the current popular numerical simulation of buried gas pipeline leakage, this paper adopts the Darcy equation of underground seepage, mass balance equation, and equation of state of gas to establish a buried gas pipeline leakage model. Geometrically, the established model is a soil cylinder with the ground as the top surface and the vertical line through the pipeline leakage point as the axis. Due to the axial symmetry, the three-dimensional buried pipeline leakage model is expressed as a two-dimensional mathematical problem. A series of key concepts about the hydrodynamic model of buried pipeline leakage and its solution are presented. A comprehensive description of the physical process (pressure and flow rate) of buried gas pipeline leakage is provided through numerical examples. Quantitative analysis was conducted on the relevant structural parameters of the model and relations of leakage flow rate with related factors of leakage. By providing a comprehensive and quantitative understanding of buried gas pipeline leakage, this paper proposes a flow rate formula and an estimation formula of leak orifice equivalent diameter of leaking buried pipelines, and provides a theoretical and data processing framework for experimental study of buried gas pipeline leakage. [ABSTRACT FROM AUTHOR]

Addressing the complex issue of lost circulation in drilling operations is crucial as it increases nonproductive time and costs. Conventional gel plugging materials often exhibit low temperature resistance, poor pumpability, and low pressure-bearing capacity. To overcome the limitations, a self-made polymer (HSA) was initially synthesized and mixed with two crosslinker agents (MBA/PEI) at room temperature to induce a new type of high-temperature-resistant and pressure-resistant polymer gel agent (HSA-G). Investigating the gel strength and plugging capacity, the vertical inverted tube observation, 71-type high-temperature and high-pressure (HTHP) instruments, and high-pressure filter with varying fracture cracks (3–5 mm) were employed. HSA-G demonstrated excellent gelation strength for 4–5 h at 140 °C, while retaining more than 57% of its gel strength after aging at 140 °C for 144 h, which is 3 times higher than the commercially available hydrolyzed polyacrylamide (HPAM + PEI). The excellent performance was attributed to the synergy between PEI-MBA, which induces tight-crosslinked interconnected structure within HSA-G, mitigating fluid losses to only 72 mL compared to 194 mL for HPAM-G, under 8.5 MPa in the HTHP sand bed at 140 °C. In the fracture leakage simulations using a 5 mm crack performed at 6 MPa at room temperature, the filtration loss of HSA-G is 300 mL, almost half that of HPAM-G, showcasing its superior plugging and high-pressure bearing performance. In conclusion, HSA-G has not only demonstrated operational effectiveness in reducing downtime costs and fluid losses but can also temporally replace cement plugging to prevent reservoir contamination in alignment with environmentally friendly practices. [ABSTRACT FROM AUTHOR]

Property-driven hardware verification provides a promising way to uncover design vulnerabilities. However, developing security properties that check for highly concealed security vulnerabilities remains a significant challenge. In this paper, we propose a scheme, called HT-PGFV, to implement hardware Trojan security property assertion automatic generation and formal security verification for Trojan-infected designs. In our scheme, we develop a hardware Trojan security property assertion generation method for automated hardware which can extract hardware Trojan security properties from Trojan-infected designs by performing the three main steps of Trojan-infected signal identification based on feature matching, influence-cone-analysis-based Trojan path identification, and information flow trace mining, and formulate them as SystemVerilog assertions. In addition, we develop a formal security verification method based on information flow analysis which can formally verify hardware Trojan security properties and detect hardware Trojans violating information flow security policies by checking the security of information flows via our developed RT-level hardware information flow security models. The proposed method is demonstrated on several Trojan benchmarks from Trust-Hub. Experimental results show that our scheme can generate hardware Trojan security property assertions for Trojan-infected designs and detect information leakage and functionality change hardware Trojans activated by external inputs or internal conditions. [ABSTRACT FROM AUTHOR]

Introduction: A continent catheterizable channel (CCC) may be a solution for patients with impaired bladder emptying and difficult transurethral access. Leakage of the CCC is a common complication. To prevent leakage, the pressure in the CCC has to be higher than the reservoir (bladder/pouch) pressure in at least one location. It has not been clearly defined through which mechanism(s) the CCC achieves continence. In this feasibility study, we measured the CCC pressure profile in adult patients with various types of CCC's with and without stomal leakage. Methods: Adult patients with a CCC on a (augmented) bladder or pouch who underwent a urodynamic investigation between January and March 2023 were included. Next to the standard urodynamic investigation, a continuous stomal pressure measurement (CSP) and stomal pressure profilometry with empty bladder (SPP‐1) and with filled bladder (SPP‐2) of the CCC were performed. Results: A total of 17 patients were included. It was technically possible to perform SPP‐1 and SPP‐2 in all patients, and to measure the CSP in 16/17 patients. The median maximum stomal pressures in SPP‐1 and SPP‐2 were 112 (interquartile range [IQR], 76–140) cmH2O and 120 (IQR, 92–140) cmH2O, respectively. Nine patients had stomal leakage during the urodynamic investigation. In five patients, the detrusor leak point pressure (dLPP) was low (<20 cmH2O). A pressure peak at the beginning of SPP‐2 was absent in all patients with stomal leakage at low dLPP. Conclusion: SPP and CSP measurement in CCCs are feasible. We found differences in SPP‐2 between patients with and without leakage at low dLPP, indicative of a role of the intravesical tunnel in continence or high dLPP. The results of this study may improve our understanding of the physiology and dynamics of CCCs as well as the management of CCC‐related complications. [ABSTRACT FROM AUTHOR]

The submerged floating tunnel (SFT) is a type that allows tunnel floating owing to the water buoyancy. SFTs are often subjected to high-water pressure and environmental loads, such as waves and currents, which differ from those experienced by typical underground tunnels. In these SFTs, a sudden, large water leak can occur owing to collisions with external objects (such as ships), mooring lines for anchoring, and structural fatigue failure. To address these unexpected situations, it is necessary to develop a disaster prevention system for leakages. However, tunnel leaks and their propagation characteristics within tunnels have not been studied in depth. In this study, numerical simulations were performed using the commercial software program FLOW-3D to evaluate the characteristics of the water flowing through the tunnel owing to local damages to tunnel segments. In the simulations, a representative cross-section of the SFT was modeled, and the water propagation characteristics with respect to the crack size and water depth were evaluated. The results confirmed that the crack size and water depth significantly affected the propagation characteristics of the leaks. The results of this study are expected to be used as useful data for the design of disaster prevention systems for leaks in SFT. [ABSTRACT FROM AUTHOR]

Due to the flexible components, damping, underactuation, and uncertainties, the control for flexible transmission system (FTS) becomes very difficult. A constraint‐following servo control is designed to address this issue. The damping and applied load of system are integrated into the constraints, so that the desired performance could be achieved by accomplishing the constraints with Udwadia–Kalaba (U–K) equation. The system is divided into two subsystems by introducing a designed fictitious control to the load end, and the controllers of subsystems are designed, respectively. Since the accurate value of uncertainty is usually unknown, a corresponding leakage type of adaptive law is designed to estimate the size of its boundary without requiring the uncertainty itself. The effectiveness and superiority of proposed controller are verified by simulations. [ABSTRACT FROM AUTHOR]

This paper provides an evaluation of the numerical method for limiting the effect of spectral leakage on the frequency normalisation results of the pavement load and displacement functions which were induced with a dynamic impulse generated during FWD tests. The main part of the paper is concerned with the presentation of a method, which can be used to effectively reduce the effect of spectral leakage on the frequency normalisation of signals obtained through pavement testing with FWD. The method developed is supported by the observed differences between the results of the backcalculations carried out for the measurement results of the test section pavement deflections, which were subjected to frequency normalisation with and without spectral leakage reduction. The signals, where the proposed spectral leakage mitigation method was applied, were the only ones for which the identified values of the elastic modulus of the asphalt layer package model increase as the frequency increases, which agrees with the generally accepted relationship observed under laboratory conditions. [ABSTRACT FROM AUTHOR]

I consider a technology holder that has to decide whether to file for a patent or rely on secrecy, and a competing firm that can enter the market through technology transfer or imitation. Acknowledging that imitation is uncertain, imperfect, and takes time to materialise, as well as that intellectual property protection is not absolute, I find that technology transfer will always occur if the technological efficiency to imitate is sufficiently low. This will happen regardless of the protection choice of the inventor. Conversely, highly efficient imitation technologies will lead to imitation instead of licensing. I also consider that a trade secret might accidentally leak and thus lose its economic value, thereby rendering secrecy less preferable to patenting. Additionally, the risk of leakage might also lead to more imitation than licensing. Finally, considering that, in practice, the probability of leakage might increase with the number of firms practising a secret, I suggest an increase in the attractiveness of the patent system. [ABSTRACT FROM AUTHOR]

The fluid's viscosity significantly affects the performance of a centrifugal pump. The entropy production method and leakage are employed to analyze the performance changes under various viscosities by numerical simulation and validated by experiments. The results showed that increasing viscosity reduces both the pump head and efficiency. In addition, the optimal operating point shifts to the left. Leakage is influenced by vortex distribution in the front chamber and boundary layer thickness in wear-ring clearance, leading to an initial increase and subsequent decrease in leakage with increasing viscosity. The total entropy production S pro , Total inside the pump rises with increasing viscosity. The different mechanisms dominate under varying conditions: Turbulent dissipation dominates at low viscosity. Under high-viscosity conditions, energy loss is primarily caused by direct dissipation S pro , D and wall entropy production S pro , W . This study provides a deeper and more objective understanding of the energy characteristics of centrifugal pumps handling fluids of various viscosity, potentially aiding in optimizing pump design and improving energy conversion efficiency. [ABSTRACT FROM AUTHOR]

Peak-to-average power ratio (PAPR) in orthogonal time frequency space (OTFS) is vital for optimizing signal efficiency, minimizing distortion, and enhancing the performance of a beyond fifth-generation (B5G) system. The paper focuses on lowering the PAPR while retaining the bit error rate (BER) and power spectral density (PSD) for 64 and 256 sub-carriers. The PAPR is minimized by using a fractal optimization process known as selective mapping (SLM) and partial transmission sequence (PTS) at the transmitting block of the OTFS framework. The combination of SLM and PTS reduces peak power by selectively modifying the phase of transmitted symbols. SLM generates multiple versions of the signal, while PTS allocates power to these versions optimally, collectively mitigating amplitude peaks and minimizing PAPR. According to the simulation results, the suggested SLM+PTS works better than the traditional SLM and PTS, achieving low spectrum leakage and PAPR improvements of 5.5 dB and 4.9dB as well as SNR gains of 2.4dB and 2.1dB. In the future, SLM+PTS may work on lowering PAPR by making computers faster, researching adaptive algorithms, and combining machine learning methods for real-time optimization in various communication settings. Complex modeling, including fractal-based SLM and PTS approaches, provides a detailed understanding of waveform behavior and interference patterns, enabling more accurate and effective hybrid PAPR reduction techniques. This combination enhances the ability to manage to mitigate non-linear distortion across various sub-carriers, crucial for the performance and efficiency of 6G OTFS modulation. [ABSTRACT FROM AUTHOR]

The operational cabin of hydrogen tube bundle containers (HTBCs) is susceptible to vibration and fatigue loads during transportation, which may result in hydrogen leakage and deflagration accidents. In this paper, a three-dimensional (3D) computational fluid dynamics (CFD) model is developed to simulate the effects of leakage diameter, leakage pressure, leakage direction and position on hydrogen leakage and diffusion in the operational cabin of HTBCs. The results demonstrate that the formation of vortex recirculation zones leads to the accumulation of flammable gas cloud (FGC) in the operational cabin. The medium leakage diameter (1.5 mm) and higher leakage pressure (20 MPa, 35 MPa) cause the operational cabin to be filled with FGC within 5 s, requiring the operational cabin to be designed with no possible ignition source inside. In addition, when hydrogen leaks from the +Z direction, the sensor responds within 0.31 s, which is 1.7 s earlier than the response time in the -Z direction, indicating that the existing sensor layout cannot meet the requirements of fast response. When the leak position (L 3) is close to the vent, the FGC volume proportion at 2 s is 19.3 % and 15.88 % lower than that of L 1 and L 2 , respectively, indicating that the leak position close to the vent can effectively slow down the accumulation of FGC. The research results have implications for the safety design of operational cabin of HTBCs, the layout of hydrogen sensors and vents, and the emergency response measures for hydrogen leakage. [Display omitted] • Numerical simulation reveals hydrogen leakage and diffusion behavior of tube bundle containers during transport. • Vortex recirculation zones cause flammable gas cloud accumulation in operational cabins. • Medium leakage (1.5 mm) and high pressure can fill the cabin with flammable gas cloud in 5 s. • Leakage direction and position affect hydrogen sensor response time. • The addition of hydrogen sensors and vents can reduce the risk of explosion. [ABSTRACT FROM AUTHOR]

AbstractBackgroundMethodsResultsConclusionThe role of early oral feeding (EOF) following esophagectomy remains debated. This study evaluates whether postoperative EOF improves patients’ quality of life.A comprehensive search was performed across eight databases to identify relevant studies. The effects of continuous variables were assessed using the mean difference (MD). The effects of dichotomous variables were assessed using the relative risk (RR).Seven studies were included in the analysis. EOF significantly improved postoperative overall quality of life [MD = 9.64, 95% CI (6.11, 13.16), p < 0.001], dysphagia [MD = −7.37, 95% CI (-14.32, −0.42), p = 0.040], and eating difficulty [MD = −6.72, 95% CI (-10.62, −2.82), p < 0.001]. However, no significant differences were observed in postoperative reflux [MD = −5.90, 95% CI (-12.52, 0.73), p = 0.080], esophageal pain [MD = −1.86, 95% CI (-5.51, 1.78), p = 0.320], anastomotic leakage [RR = 0.70, 95% CI (0.37, 1.35), p = 0.290], and pulmonary infection [RR = 0.44, 95% CI (0.15, 1.35), p = 0.150].EOF after esophagectomy appears to improve patients’ quality of life; however, these findings are constrained by the limited number and quality of studies. Further research is needed to validate these results. [ABSTRACT FROM AUTHOR]

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Power devices rely on ideal edge termination to suppress the electric field crowding and avoid premature breakdown before the material's critical field is reached. In this work, a hybrid electric field management configuration, featuring the combination of beveled-mesa (BM) termination and high-k oxide BaTiO3 field plate (FP), was implemented in Ga2O3 Schottky barrier diodes (SBDs). This BMFP-SBD realizes a breakdown voltage (BV) of 1.7 kV with extremely low reverse leakage current, outperforming the BM terminated SBD with BV of 0.64 kV and bare SBD with BV of 0.22 kV. Based on the temperature-dependent reverse characteristics, the dominant leakage mechanism transforms from Poole–Frenkel (P–F) emission in BM-SBD to variable-range-hopping (VRH) in BMFP-SBD at high bias. In particular, under switching conditions of di/dt up to 420 A/μs, the BMFP-SBD exhibits superior dynamic switching characteristics with a short reverse recovery time of 10.1 ns, which are comparable with those in advanced commercial SiC SBDs. These findings underscore the potential of Ga2O3 SBD enabled by BM and high-k FP edge termination for high-speed and high-voltage power electronics applications. [ABSTRACT FROM AUTHOR]

Predicting impacts of potential carbon dioxide (CO2) leakage into shallow aquifers that overlie geologic CO2 storage formations is an important part of developing reliable carbon storage technology. To quantifying the effect of permeability anisotropy, a three-dimensional hypothetical reservoir model was formulated to analyze the migration behavior of CO2 under diverse permeability anisotropy scenarios. Sensitivity analyses for parameters corresponding to the permeability anisotropy and the leakage rate are conducted, and the results suggest that permeability anisotropy significantly affect the CO2 migration characteristics. Increasing the parameter of vertical/horizontal permeability ratio results in longer CO2 migration distances, which enhances the aqueous phase ratio and safety through more interaction with the aquifer, but also raises the potential of the leakage reaching the ground surface due to higher gas ratio. A comprehensive understanding of these dynamics is crucial for implementing effective monitoring and management strategies. [ABSTRACT FROM AUTHOR]

High‐efficiency large‐area flexible organic photovoltaic (OPV) modules are still challenging. Electrical shunt and shortage generally occur due to surface roughness or spikes that result in low efficiency. In this work, a thick electron transporting layer (ETL) of zinc‐chelated polyethylenimine (PEI‐Zn) is introduced to smoothen the surface of silver nanowires (AgNWs) transparent electrodes. The smoothened surface of AgNWs electrodes helped to suppress the electrical leakage or shortage. Thicker PEI‐Zn layers are required to overcome the open‐circuit voltage (VOC) loss when the device area increases. For large‐area OPV modules on AgNWs electrodes, a high thickness of PEI‐Zn up to 350 nm can deliver high VOC as well as power conversion efficiency (PCE). Based on the AgNWs transparent electrode coated by thick PEI‐Zn ETL, a PCE of 12.50% is achieved for 35.2 cm2 flexible OPV modules certified by a third party. The modules exhibited good illumination stability and mechanical flexibility. [ABSTRACT FROM AUTHOR]

The pressure decaying test is traditionally used to detect leakage in pneumatic actuators; however, it is time-consuming as it is performed between cycles of actuation. To date, there is a notable lack of real-time, data-driven machine learning methods to detect such leakages. Such leakage prediction is important to determine the lifecycle of the actuator and the exerting force to seal the vacuum chamber. This study aims to employ machine learning techniques to predict the categories of normal and leaked pressure loss ratio (PLR) in real-time during different number of pneumatic actuators cycles. The data was collected using a two-way factorial design with center points for the cycle test setting parameters. Seven parameters were recorded and undergo the training and test phase. Additionally, multiple model architecture was employed, each performing binary classification for each class to predict the PLR. Correlation analysis shows that pressure reading of each "open" and "close" inlets have better correlation for predicting the leakage with 0.216 and 0.183 respectively. The top performing model for each class is K-Nearest Neighbors (KNN) and Multilayer Perceptron (MLP). For the model 1, the KNN model achieved the highest accuracy of 93.86%, with an AUC of 0.94 in ROC analysis. Meanwhile, for the Model 2, utilizing MLP model attained an accuracy of 89.36% and an 84.87% mean-harmonic score. This study demonstrates that real-time machine learning can effectively predict leakage in pneumatic actuators, with the potential for further improvement through the inclusion of more data and increased setting points in the cycle test. [ABSTRACT FROM AUTHOR]

In this study, the maximal reduction of neutron leakage into the treatment room and bunker walls was evaluated by placing three stratified layers of PL/hBN and PL/B4C at distinct spatial coordinates within a medical linear accelerator facility. Simulations were conducted using the MCNPX code, focusing on "Photon flux per therapeutic X-ray dose" and "Neutron leakage and neutron density per therapeutic X-ray dose." The results indicated that adding PL/hBN and PL/B4C layers achieves the desired dose with a lower photon flux. The PL/hBN layer in a better proportion reduced flux compared to the PL/B4C layer. It was found that the PL/hBN layer can reduce neutron leakage and density in the air by up to 60.43 % and 50.08 %, respectively, while the PL/B4C layer achieved reductions of 44.32 % and 34.86 %. Additionally, reductions in neutron leakage and density within the bunker walls reached 95.61 % and 86.22 % with the PL/hBN shield, and up to 80.46 % and 70.59 % with the PL/B4C shield. These findings underscore the effectiveness of these layered neutron shielding measures in reducing neutron populations within the treatment room air and enhancing bunker protection. [ABSTRACT FROM AUTHOR]

In modern industrial production, unsupervised anomaly detection methods have gained significant attention due to their ability to address the challenge posed by the scarcity of labeled anomaly samples. Among them, unsupervised anomaly detection methods based on reverse distillation (RD) have become a mainstream choice, which has attracted extensive research due to their excellent anomaly detection performance. However, there is a problem of "feature leakage" in the RD model, which may lead to non-anomalous regions being incorrectly identified as defects. To solve this problem, we propose a Normal Feature-Enhanced Reverse teacher–student Distillation (NFERD) method. Specifically, we designed and incorporated a normal feature bank (NFB) module into the basic RD network. This module stores normal features extracted by the teacher model, assisting the student model in learning normal features more efficiently, thereby addressing the problem of "feature leakage". In addition, to effectively fuse the feature maps extracted by the student model with the feature maps in NFBs, we designed a Hybrid Attention Fusion Module (HAFM), which ensures the preservation of key information during the feature fusion process by the parallel processing of spatial and channel attention mechanisms. Through experimental verification on two publicly available datasets, i.e., MVTec and KSDD, our method outperformed the existing mainstream methods in both image-level and pixel-level anomaly detection. Specifically, we achieved an average I-AUROC score of 99.32% on MVTec and a 98.75% P-AUROC on the KSDD, showing clearer segmentation results, especially in complex scenarios. Furthermore, our method surpassed the second-best method by over 1.4% PRO on MVTec, demonstrating its effectiveness. [ABSTRACT FROM AUTHOR]

An Axial Piston Pump (APPs), suitable for high pressure and high efficiency, is used as the source of fluid power in the hydraulic system. Due to the compact design and relative motion between various parts, it causes wear in parts thus leakage introduce between various moving parts which work under tight tolerance. Multiple faults in an axial piston pump occur simultaneously after a long time of operation due to harsh working conditions and heavy loads. Faults in the pump deteriorate the pump's performance and limit the operating range of the pump. Estimation must account for random and uncertain characteristics, and accurate wear prediction is difficult. Effective diagnosis improves pump dependability and performance. An approach based on simulation is utilized to model the impact of faults like leakage through eccentricity in piston-cylinder arrangement with increasing severity of clearance between piston-cylinder arrangement and its effect on the pump performance. As the clearance with different eccentricity between the piston and cylinder arrangement increases, outlet pressure and discharge of the pump remains unaffected up to a critical value of severity. After further increasing severity, outlet pressure and discharge reduce monotonically and saturate at a single value in extremely severe conditions. With increasing the severity of eccentricity in the piston-cylinder arrangement and increasing the severity of clearance, a critical threshold value shifts to a lower magnitude. [ABSTRACT FROM AUTHOR]

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This work focused on the leakage of the composite pressure vessel with a structure consisting of an aluminum alloy inner liner, a composite winding layer, and an aluminum covering. Through applying the finite element simulation approach and leakage rate test, it was found that the average strain of the winding layer in the lap region at the pressure of 46 MPa is 0.0078. Additionally, the leakage rate of the covering adhesive joint was investigated by considering the deformation, revealing that the leakage rate increases with increasing test pressure. The leakage rate at the lap region with a length of 18 mm is 2.05 × 10−7 Pa·m3/s at 0.0078 strain decreasing by 1.46 and 2.31 times compared to those under 12 and 7 mm lengths, respectively. The leakage rate exhibits a strict inverse correlation with the length of the leakage path under a pressure of 0 MPa. Additionally, when the deformation remains below the critical strain threshold (approximately 0.6%), the relationship between pressure and leakage rate shows a linear positive correlation. When the deformation of the component exceeds the critical strain threshold, the leakage rate of the component is significantly affected by its deformation and an increase in overall deformation results in a greater increase in leakage rate. The relationship between the two exhibits a non‐linear trend. This work provides strong technical support for the leakage assessment of composite pressure vessels. Highlights: Deformation of the pressure vessel was analyzed through theoretical and simulation approaches.Establishing the relationship between deformation and pressure in metal–metal lap structures.Leakage analysis for different metal–metal lap lengths and deformation conditions. [ABSTRACT FROM AUTHOR]

Honey vaults are useful tools for password management. A vault usually contains usernames for each domain, and the corresponding passwords, encrypted with a master password chosen by the owner. By generating decoy vaults for incorrect master password attempts, honey vaults force attackers with the vault's storage file to engage in online verification to distinguish the real vaults, thus thwarting offline guessing attacks. However, sophisticated attackers can acquire additional information, such as personally identifiable information (PII) and partial passwords contained within the vault from various data breaches. Since many users tend to incorporate PII in their passwords, attackers may utilize PII to distinguish the real vault. Furthermore, if attackers may learn partial passwords included in the real vault, it can exclude numerous decoy vaults without the need for online verification. Indeed, both leakages pose serious threats to the security of the existing honey vault schemes. In this paper, we explore two attack variants of the inspired attack scenario, where the attacker gains access to the vault's storage file along with acquiring PII and partial passwords contained within the real vault, and design a new honey vault scheme. For security assurance, we prove that our scheme is secure against one of the aforementioned attack variants. Moreover, our experimental findings suggest enhancements in security against the other attack. In particular, to evaluate the security in multiple leakage cases where both the vault's storage file and PII are leaked, we propose several new practical attacks (called PII-based attacks), building upon the existing practical attacks in the traditional single leakage case where only the vault's storage file is compromised. Our experimental results demonstrate that certain PII-based attacks achieve a 63–70% accuracy in distinguishing the real vault from decoys in the best-performing honey vault scheme (Cheng et al. in Incrementally updateable honey password vaults, pp 857–874, 2021). Our scheme reduces these metrics to 41–50%, closely approaching the ideal value of 50%. [ABSTRACT FROM AUTHOR]

Biogas, a fuel derived from organic waste, has gained popularity as a sustainable energy source. The adaptability of biogas allows its utilization for electricity and heating. This study aims to evaluate the risk of biogas leakage using ALOHA gas dispersion modeling and Bowtie analysis to identify hazard zones and evaluate the effectiveness of preventive and mitigation measures. The research method using Gas dispersion modeling in ALOHA software can simulate the spread of leaked biogas, identify potential hazard zones, and inform emergency response planning. The results show that gas dispersion reaches up to 296 meters from the leak source in a worst-case scenario without ignition, with significant implications for safety. The ignition scenario produces high thermal radiation, further exacerbating the risk. In conclusion, these findings highlight the intolerable risk of biogas leakage, requiring comprehensive risk mitigation measures. This study recommends the implementation of a robust control system, routine maintenance, and emergency response plan to ensure the safety and sustainability of biogas facility operations. [ABSTRACT FROM AUTHOR]

The evolution of tip region vortices has a significant influence on the aerodynamic performance of the turbine. Most studies on squealer tip optimization focused on enhancing the blockage effect of the vortices inside the clearance but had limited effect on controlling the vortices outside the clearance. In this paper, both the vortices inside and outside the clearance are controlled based on the trailing edge suction side cutback in a non-cooled turbine. The results indicate that inside the clearance, the scraping vortex plays a crucial role in reducing leakage. The cutback enhances the strength of the scraping vortex, thereby expanding the effective blockage range. While outside the clearance, the tip leakage vortex breakdown exacerbates its dissipation effects, leading to a significant loss downstream of the blade. The cutback injects greater fluid momentum into the tip leakage vortex, leading to increased mixing loss between leakage jet and mainstream. Concurrently, this also inhibits the tip leakage vortex breakdown, resulting in a notable reduction in its dissipation loss. The combined impact effectively controls the total leakage loss. It has been demonstrated that there exists an optimal cutback length for the suction side squealer rim at the trailing edge, which can be determined by setting the cutback opening at the initiation of the tip leakage vortex breakdown. The aforementioned effects of the cutbacks are prominently observed under different operating conditions, which indicates that the cutbacks possess good applicability in a certain range. This offers valuable guidance for tip region vortices control and squealer tip optimization. [ABSTRACT FROM AUTHOR]

This paper introduces a casing bionic chamber structure into the transonic compressor, inspired by the airflow control mechanisms observed in dragonfly wings. Numerical simulations are employed to examine how variations in the height and placement of the casing bionic chamber affect compressor performance and flow field structure. The results indicate that the trapped vortex generated by the casing bionic chamber increases the airflow resistance near the casing, reduces the clearance leakage flow, and suppresses the influence of the leakage vortex along the pitchwise direction. The optimal placement for the casing bionic chamber is near the starting position of the leakage vortex. The inhibition of the clearance leakage is enhanced and then weakened with the increased chamber height. When the chamber is located near the leading edge to the trailing edge, with a height equal to 0.6% of the blade height, the leakage flow rate is reduced by 1.82%. [ABSTRACT FROM AUTHOR]

In this study, we introduce an automated design method for Quantum Cascade Laser (QCL) active region (AR) structure employing a generative neural network, termed an inverse network, which creates the structure designs based on specific k · p metric inputs related to device performance. The training dataset, derived from an earlier study, was selectively filtered to remove entries affected by energy-level hybridization or splitting, yielding ∼300 000 valid entries. A pre-trained forward network that processes QCL-AR structures and returns corresponding k · p metrics serves as the evaluator for the inverse network, supplanting traditional loss functions such as mean squared error or mean absolute error. This strategy overcomes the problem of non-uniqueness in the mapping from k · p metrics to QCL-AR structures. The inverse network incorporates a random layer, allowing it to produce a variety of QCL-AR structures from identical predicted metrics, thereby increasing the model's practicality. Performance testing indicates high accuracy in the metrics of the generated QCL-AR structures, with the coefficient of determination, R2 scores, for key energy-level differences between the upper-laser (ul) level and the lower-laser level, E43, and between the next-higher-energy level above the ul level and the ul level, E54, of 0.9153 and 0.9701, respectively; and for the electron lifetimes τ43 and τ54 of 0.9568 and 0.9175. As an example, we show how the network generates a QCL-AR structure with the potential for low threshold-current density by suppressing shunt-type carrier leakage from the ul level through a higher energy AR state. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to investigate the sealing performance of different deep groove mechanical seals by considering the changing law of dynamic pressure effect and temperature gradient caused by high speed and high pressure. Design/methodology/approach: A thermohydrodynamic lubrication model (THD) of the mechanical seal was constructed and solved using the commercial software FLUENT. The pressure and temperature distributions of the fluid under different groove types, as well as the sealing performance under different pressures, rotational speeds and sealing gaps, are obtained. Findings: The annular groove (AG) can effectively reduce the temperature, and the T-type spiral groove (STG) can effectively inhibit the leakage. The increase of pressure and rotational speed leads to the enhancement of dynamic pressure effect and the increase of leakage, while the sealing gap increases and the leakage increases while taking away more heat. The choice of groove type is very important to the impact of sealing performance. Originality/value: In consideration of the beneficial effect of deep grooves on cooling performance, the viscous temperature equation and the impact of the thermodynamic lubrication model are evaluated in conjunction with the sealing performance of four distinct groove types. This approach provides a theoretical basis for the optimal design of mechanical seals. Peer review: The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2024-0184/ [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to improve the seal performance by proper design of the cavity shape of the damping holes, especially the rotordynamics characteristics of the hole-pattern damped seal (HPDS). Design/methodology/approach: A new damping seal structure that comprises a circle-shaped cavity and two directional leaf-shaped cavities with a dovetail-shaped diversion groove is proposed. The comparative study on the sealing characteristics of dovetail-shape, leaf-shape and classical circular HPDSs was carried out using ANSYS CFX. Findings: The dovetail-shaped HPDS significantly outperformed two other damping seal designs in leakage and rotordynamic performance. At a rotating speed of 7,500 rpm, it showed a 25% reduction in leakage, a 23% increase in average effective damping and a 119% increase in average effective stiffness. The cross-coupled stiffness Kxy shifted from positive to negative, reducing circumferential flow. The dovetail's inclined leaf-shaped grooves create a double vortex that slows jet velocity in the seal clearance and alters spiral flow direction, resulting in a uniform pressure distribution and enhanced rotor stability at low frequencies. Originality/value: This study proposes a novel HPDS with dovetail-shaped diversion grooves. The seal can realize the simultaneous improvement of rotordynamics and leakage characteristics compared to the current seal structure. Peer review: The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2024-0127/ [ABSTRACT FROM AUTHOR]

The characteristics of the planar premixed flame near the flammability limit were investigated by employing the Zel'dovich-Liñán two-step reaction model, focusing on the fast recombination regime. The structure of the reaction zone was numerically analyzed to examine the differences in flame characteristics between first-order and second-order recombination reactions, under the limit of a large chain branching Zel'dovich number, β. As the ratio of reaction rates between branching and recombination decreases, the concentration of chain carriers also decreases, leading to a reduction in flame speed, as expected. In the flammability limit condition where the flame speed is zero, there are notable differences in combustion characteristics between first and second recombination. As the flammable limit is approached, the ratio of reaction rates approaches the mathematical constant e in first-order recombination due to substantial fuel leakage from the reaction zone, whereas in second-order recombination, the ratio of reaction rates approaches zero as there is no fuel leakage. An asymptotic analysis was employed to derive the relevant expressions for the ratio of reaction rates at the flammable limit. [ABSTRACT FROM AUTHOR]

The characteristic of one-shot voice conversion is the ability to transform identity using only a single speech sample from the target speaker. However, the intricate interactions and dynamic variations of acoustic features pose challenges for existing methods to fully disentangle the speaker's timbre from other acoustic features, resulting in the leakage of the original speaker's timbre in the converted audio. To tackle this challenge, this paper proposed the IPFD-VC model to incorporate information perturbation and feature decoupling. The model initiated three perturbation operations to the voice signal through an information perturbation module in order to remove redundant information from input and the prosody encoder. Then it enabled to feed the processed signal into each encoders. The model employed a strategy of minimizing mutual information to further decouple the acoustic features, thereby diminishing their correlation with the speaker's timbre characteristics. The decoder and vocoder subsequently output the convert audio. The experiments show that the IPFD-VC model achieves scores of 3.72 for voice naturalness and 3.68 for speaker similarity. In comparison to the advanced UUVC model, the model reduced the Mel-cepstral distortion by 0. 26 dB. The IPFD-VC model effectively decouples acoustic features, captures the target speaker's timbre, preserves the source language content and rhythmic variations, and mitigates the risk of speaker timbre leakage. [ABSTRACT FROM AUTHOR]