To optimize the ignition and combustion performance of nanosecond pulsed surface dielectric barrier discharge (nSDBD) electrodes for NH3/air mixtures, an experimental investigation was conducted by varying the number of radial copper strips (number of conductive areas: CAN = 6, 9, 12) and width (width of conductive areas: CAW = 1 mm, 2 mm, 3 mm) on the powered electrode. Experiments were performed in a constant-volume combustion chamber under an NH3/air mixture with an initial temperature of 363 K, initial pressure of 2 bar, and an excess air ratio (lambda) of 1.0. Diagnostics were implemented using high-speed camera and pressure sensors, with nanosecond pulse parameters set to 100 pulses and a pulse repetition frequency of 20 kHz. The regulatory effects of electrode structural parameters on flame kernel development, flame propagation, and combustion characteristics were systematically analyzed. The results indicate that the CAN and CAW directly govern the flame kernel morphology and evolution by modulating the distribution of discharge energy. Under the optimal configuration of CAN = 6 and CAW = 3 mm, the electric field distribution is uniform with moderate energy density, leading to the stable generation of active free radicals (e.g., O, OH, H). Consequently, the synchronization of flame kernel ignition is maximized, with a consistent, stable number of 6 initial kernels, without obvious fusion or extinction. This configuration significantly compresses the flame development time (FDT = 8.5 ms) and flame rise time (FRT = 26.5 ms). Additionally, the combustion pressure peak occurs earliest (at 54 ms), and the cumulative heat release rate increases the fastest in the early stage. The findings demonstrate that the nSDBD electrode with CAN = 6 and CAW = 3 mm achieves efficient regulation of combustion performance in NH3/air mixtures by leveraging multi-scale synergy among "electric field distribution-energy deposition-active species generation-flame kernel development-combustion timing". This study provides critical technical parameters and theoretical support for the optimal design of ignition systems in ammonia-fueled engines.
An r-uniform hypergraph is called t-union-free if any two distinct subsets of at most t edges have distinct union. The study of union-free hypergraphs has multiple origins and a long history, dating back to the works of Kautz and Singleton (1964) in coding theory, Bollobás and Erdős (1976) in combinatorics, and Hwang and Sós (1987) in group testing. Let U_t(n,r) denote the maximum number of edges in an n-vertex t-union-free r-uniform hypergraph. In this paper, we determine the asymptotic behavior of U_t(n,r), up to a lower order term, for almost all t≥ 3 and r≥ 3. This significantly advances the understanding of this extremal function, as previously, only the asymptotics of U_2(n,3) and U_2(n,4) were known. As a key ingredient of our proof, we establish the existence of near-optimal locally sparse induced hypergraph packings, which is of independent interest.
We investigate a class of zero-flux chemotaxis-growth systems featuring nonlinear local and non local reaction terms, as well as a gradient-dependent damping, given by {u(t) = Delta u - chi del .(u del upsilon) + au(rho) - b(integral(Omega) u(beta))(delta) - c|del u|(gamma), in Omega x (0, T-max) tau upsilon(t) = Delta upsilon - upsilon + u, in Omega x (0, T-max), where chi, a, b, c > 0, rho, beta, delta , gamma >= 1 and tau is an element of (0,1). Assuming that Omega subset Omega subset of R-n (n >= 1); is a bounded domain with smooth boundary and that the initial data (u(0), tau upsilon(0)) are sufficiently regular, we prove the existence of global (i.e., T-max = infinity), uniformly bounded classical solutions under suitable structural conditions on the exponents defining the reaction term and the dimension n. A central insight of our analysis is that, in contrast to classical scenarios where rho <= beta typically ensures automatic control of the total mass integral(Omega) u, the regime rho > beta makes that the structure of the source term alone does not suffice to guarantee mass boundedness. Accordingly, the global boundedness of solutions is achieved via a two-tiered strategy: first, we identify a parameter regime in which the total mass remains uniformly bounded in time; second, under further constraints on the model parameters, we establish uniform-in-time boundedness of classical solutions in stronger norms, specifically in L-infinity(Omega). These results offer further insight into the interplay between chemotactic aggregation, gradient-driven dissipation, and nonlocal reaction effects, contributing to the analysis of blow-up prevention in structured chemotaxis models.
Powered patient-transfer beds and smart transport systems are increasingly being introduced in hospitals to reduce the manual-handling burden and support patient movement. When such equipment is used for time-critical transfers, finite battery capacity and state-of-charge-dependent availability can couple transport decisions with operating-room schedules. This paper formulates a heterogeneous three-stage surgical scheduling problem that jointly optimizes patient selection, clinical-stage sequencing, PHU/OR/PACU resource assignments, ITB transport-task assignment and order, and SOC-triggered charging. Unlike conventional surgery-scheduling models that treat inter-stage transport as exogenous or resource-free, and unlike AGV logistics models that take clinical service processes as given, the proposed formulation makes clinical and transport-energy decisions mutually endogenous: the clinical schedule releases transport tasks, whereas ITB availability and charging feed back into patient arrival times and medical-resource utilization. The resulting problem has a large decision space with tightly coupled scheduling and energy constraints. We propose QH-MLNS, a reinforcement-learning-enhanced, multi-destruction-strength large neighborhood search algorithm that combines a destroy–repair strategy with multiple destruction strengths, Q-learning-based adaptive operator selection, and dynamic dual-pool retention. The study examines a deployment regime in which battery-powered transfer devices are shared and charging can restrict their availability; it does not assume that such devices are already standard in all hospitals. On the tested resource-constrained and resource-abundant scenarios, QH-MLNS yields 30.3% and 52.5% higher mean hypervolume and 45.6% and 96.2% lower mean inverted generational distance than H-MLNS and MLNS, respectively.
By regulating the CoCrNiMo0.5 laser cladding coating with varying amounts of added element Si, the influence of Si on the microstructure evolution and wear resistance of the cladding coating was systematically investigated, and a micromechanical testing scheme for the cladding coating was innovatively proposed. The results show that: with increasing Si addition, the un-melted Mo particles gradually decrease, the proportion of intermetallic compounds in the coating gradually increases. When the Si molar ratio reaches 0.8, the area fraction of FCC phase in the cladding coating is 19.3%, while the total fraction of Mo–Si-rich HCP-type intermetallic compounds and Ni–Si-rich SC-type intermetallic compounds approaches 80%. In this case, the FCC phase is distributed in the interstices between the two intermetallic phases, suggests a potential toughening effect, and the wear resistance of the coating is optimized. Combined with the micromechanical properties of the cladding coating, it can be referred that when the Si molar ratio is 0.8, the coating exhibits a greater tendency towards brittleness and hardness, and there may be a risk of failure under prolonged wear damage. This preliminarily confirms the guiding significance of micromechanical properties for evaluating the wear resistance of the cladding coating.
