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This article challenges standard accounts about technological disillusionment in the late 1960s and 1970s that locate opposition to new technologies primarily in environmentalists and the "New Left" or declining trust in expertise. Looking at the critics of the Anglo-French supersonic jet Concorde in Britain, it argues for the importance of political economy to understand the demise of techno-nationalism. Drawing on debates within government, Parliament, the press, and extraparliamentary opposition, the article demonstrates that actually economic and industrial critiques-often voiced privately within the state-were decisive. What united these ideologically diverse opponents was not environmentalism but a shared wariness of state power and the conviction that official deception sustained a looming commercial disaster. It also shows how a lack of transparency and powerful state propaganda masked Concorde's effective cancellation, which demonstrated a deep rejection of techno-nationalism. The conclusion reflects on why Britain sustained its supersonic commitment longer than the United States.

Shock waves, disturbances that propagate with supersonic velocity in a fluid, are prevalent in nature and across nearly all natural sciences. They find diverse applications in fields such as medicine, aerospace engineering and physical chemistry, where experiments are conducted mostly in macroscopic tubes with an inner diameter ranging from more than 1 mm up to the meter scale. While the theoretical framework for macroscopic shock waves is well-established, the behavior of shock waves in capillaries with diameters in the micrometer range-referred to as "micro-shock waves"-remains largely unexplored. This paper presents novel experimental investigations on the collision of shock waves in micro-capillaries, a fundamental research that has never been done before. These investigations, involving both steady and unsteady drivers, are of significant importance for shock wave physics in general, especially given the limited research on unsteady shock wave collisions. Even more, they play a crucial role in the analysis of micro-shock waves, since they contribute to a more complete characterization of the post-shock region. With the growing interest in microfluidic devices, this research is also important to advance the understanding of supersonic flows at the microscale. Even in the application of high-repetition-rate laser sources, micro-shock wave physics is involved.

While supersonic cooling revolutionized spectroscopic studies of neutral molecules, cooling molecular ions remains far more challenging, especially for ions generated from electrospray ionization (ESI). Cryogenic cooling has been transformative, particularly for ESI-produced ions, by enabling intrinsically cold spectroscopic interrogation of solution-phase species transferred into the gas phase. This perspective focuses on cryogenic photoelectron spectroscopy (PES) and photodetachment spectroscopy (PDS) of complex anions produced by ESI and cooled in a 3D Paul trap, a platform that has been widely adopted because of its relative simplicity and robust performance. We discuss the technical evolution from the initial ESI-PES for solution species to cryogenic ESI-PES with a magnetic-bottle analyzer, and the current cryogenic PDS and high-resolution photoelectron imaging. We emphasize significant advances enabled by coupling the cryogenic 3D Paul trap first to ESI sources-highlighting studies of temperature-dependent phenomena, solution-phase chemistry in the gas phase, nonvalence excited states, vibrationally induced autodetachment, and resonant PES-and more recently to a laser-vaporization cluster source, demonstrating more effective vibrational cooling for cluster ions than supersonic expansion.

2,8-Bis (2,4,6-trinitrophenyl)-5,11-dioxo-2,4,6,8,10,12-hexacyclo[7.3.0.03,7]dodecane-1(12),3,6,9-tetraene (TNBP) is a new thermally stable explosive renowned for its exceptional detonation performance and thermal stability, making it highly valuable for applications in supersonic weapons, aerospace engineering, and ultra-deep well perforation. This study utilizes reactive molecular dynamics simulations to elucidate the thermal decomposition mechanism and kinetics of TNBP. Under both non-isothermal and isothermal conditions, the initial decomposition stages involve key reactions such as intermolecular oxygen transfer, dimerization, and NO dissociation. The primary decomposition products include small molecules like NO2, NO, N2, H2O, CO2, H2, HNO2, and HNO, alongside a range of clustered molecular species. Structural analysis indicates that TNBP's highly stable cyclic framework restricts cluster growth at lower temperatures. As the temperature rises, the rapid dissociation of H and N atoms from these clusters promotes a structural transition toward chain-like configurations. Furthermore, unlike RDX, TNBP pyrolysis generates a significant quantity of clusters, which effectively suppress the migration of atoms and retard heat transfer-this is identified as a crucial factor contributing to its superior thermal stability. Finally, kinetic parameters, including the activation energy (Ea) and pre-exponential factor (lnA), were determined for different stages of the pyrolysis process through reaction kinetics modeling. This work provides fundamental insights into TNBP's behavior under extreme high-temperature conditions, offering a theoretical basis for the design and synthesis of novel heat-resistant energetic materials. Molecular dynamics simulations of the thermal decomposition behavior of TNBP were conducted using the Large-scale Atomic/Molecular Parallel Simulator (LAMMPS) in conjunction with the ReaxFF/lg reaction force field. First, a 2 × 2 × 1 supercell model was constructed based on X-ray diffraction crystal data. To obtain a reasonable initial equilibrium configuration, the system underwent 5 ps of geometric optimization under NPT conditions (300 K, 1 atm) with a time step of 0.1 fs and a temperature damping coefficient of 10 fs. The applicability of the ReaxFF/lg force field in describing the TNBP system was verified by comparing crystal parameters with the interatomic radial distribution function. To investigate the impact of elevated temperatures on TNBP thermal decomposition, two heating simulation protocols were employed: First, the system was heated from 300 to 2700 K at a rate of 12 K·ps-1 under NVT conditions. Second, isothermal kinetic simulations of 200 ps were conducted at four temperatures: 2500 K, 2750 K, 3000 K, and 3250 K. During simulations, molecular species information and thermodynamic data were output every 10 fs, with bond-level evolution and atomic trajectories recorded synchronously.

A consistent kinetic modeling and discretization strategy for compressible flows across all Prandtl numbers and specific heat ratios is developed using the quasiequilibrium approach within two of the most widely used double-distribution frameworks. The methodology ensures accurate recovery of the Navier-Stokes-Fourier equations, including all macroscopic moments and dissipation rates, through detailed hydrodynamic limit analysis and careful construction of equilibrium and quasiequilibrium attractors. Discretization is performed using high-order velocity lattices with a static reference frame in a discrete velocity Boltzmann context to isolate key modeling aspects such as the necessary requirements on expansion and quadrature orders. The proposed models demonstrate high accuracy, numerical stability, and Galilean invariance across a wide range of Mach numbers and temperature ratios. Separate tests for strict conservation and measurements of all dissipation rates confirm these insights for all Prandtl numbers and specific heat ratios. Simulations of a thermal Couette flow and a sensitive two-dimensional shock-vortex interaction excellently reproduce viscous Navier-Stokes-Fourier-level physics. The proposed models establish an accurate, efficient, and scalable framework for kinetic simulations of compressible flows with moderate supersonic speeds and discontinuities at arbitrary Prandtl numbers and specific heat ratios, offering a valuable tool for studying complex problems in fluid dynamics and paving the way for future extensions to the lattice Boltzmann context, by application of correction terms, as well as high-Mach and hypersonic regimes, employing target-designed reference frames.

Wind tunnels serve as an essential infrastructure for aerodynamic research and aerospace vehicle development, and pressure vessels are the most important type of structure in transonic and supersonic wind tunnels. Conventional structural design methodologies exhibit critical limitations including over-reliance on empirical specifications, computational inefficiency, and excessive conservatism. Although data-driven surrogate-based optimization approaches partially mitigate these issues, their generalizability variable operation condition remains limited. This study proposes a knowledge-embedded hierarchical Kriging (KEHK) framework that synergistically integrates the pressure vessel design specification with adaptive multi-fidelity modeling. The methodology introduces three key innovations: a knowledge-embedded sequential sampling method based on pressure vessel design specification, an adaptive hierarchical Kriging architecture incorporating multi-fidelity training samples, and a novel condition-mapping protocol to enhance cross-scenario generalizability. The experimental validation of a transonic wind tunnel acceleration section demonstrated a 26.2% structural weight reduction while maintaining operational integrity, coupled with a 150&#x2009;&#xd7;&#x2009;computational efficiency improvement over conventional finite element analysis for single-iteration simulations. Comparative evaluations revealed the KEHK&#xa0;model's&#xa0;superior generalization capability, achieving a prediction error of <15% across 0.1-2.0 the operational pressure ranges, significantly outperforming the conventional hierarchical Kriging, BPNN and nonadaptive KEHK variants. These advancements have established the framework as a robust solution for next-generation wind tunnel engineering applications, effectively bridging the gap between the computational efficiency and operational reliability.

Metastable helium lidar represents a promising technique for upper atmospheric detection; however, its implementation entails several critical scientific challenges that necessitate thorough experimental validation and refinement under controlled laboratory conditions. To address this need, we have developed a dedicated laboratory simulation instrument comprising three key components: (1) a metastable helium source chamber, (2) an integrated transmitter and receiver system, and (3) a precise experimental timing sequence. The metastable helium source, housed within the main vacuum chamber, is a pulsed supersonic plasma jet generated via gas discharge. The integrated transmitter and receiver emulate a lidar configuration, enabling the investigation of the backward fluorescence spectrum of metastable helium. The experimental timing sequence governs the operation of individual components and facilitates baseline noise subtraction through precise temporal alignment. A direct absorption spectroscopy detection scheme can also be implemented on the setup to perform calibration experiments. The system achieves a metastable helium atom density of &#x223c;1010&#xa0;cm-3. The density, velocity distribution, and flow speed of metastable helium atoms in the source can be controlled by changing the discharge nozzle configuration and discharge conditions. This simulation instrument enables the investigation of the saturation effect in the absorption spectrum of metastable helium atoms, providing valuable laboratory data for the design and data analysis of helium lidar systems. Ultimately, it also serves as a calibration tool for both ground-based and future spaceborne helium lidar devices.

Experimental measurements of the kinetics of the CH + N2O reaction are reported for the first time for the temperature range of 32(3) - 110(4) K using the recently commissioned highly instrumented low temperature reaction chamber (HILTRAC). Furthermore, we report the characterization of a new Laval nozzle to achieve uniform supersonic flow (USF) temperatures of 73(3), 86(4), and 110(4) K with an argon buffer gas. CH radicals generated from photolysis of CHBr3 at 248 nm were detected by laser-induced fluorescence using the CH B&#xa0;2&#x3a3;- &#x2190; X 2&#x3a0; (1,0) Q2(1) transition near 364 nm, measuring the pseudo-first-order rate coefficients in the presence of N2O. From these experiments, the reaction rate coefficient at 32(3) K was measured to be 1.7(1) &#xd7; 10-10 cm3 molecule-1 s-1 and is at least a factor of 2 greater than the previously measured value at room temperature. The reaction rate coefficient was found to exhibit a positive temperature-dependence below 50 K, while exhibiting a negative temperature-dependence at higher temperatures. We also report the reaction potential energy surface for this reaction, performing ab initio calculations at the CCSD(T)/aug-cc-pV(Q+d)Z//M06-2X-D3/aug-cc-pV(Q+d)Z level of theory. From this, we identified reaction pathways leading to exothermic product channels for NO + HCN, NO + HNC, N2 + HCO, and N2 + H + CO, suggesting that NO + HCN are the primary reaction products due to the barrierless nature of this reaction pathway. Finally, a modified Arrhenius fit to all experimental data (32-1300 K) yields k(T) = (9.3(4) &#xd7; 10-11) &#xd7; (T/300)-1.03(6) exp(-52(5)/T) cm3 molecule-1 s-1, which can be incorporated into astrochemical models to better understand the nitrogen-based chemistry of the interstellar medium.

The rapid increase in global cooling demand, particularly in regions with high solar potential, has emphasized the urgent need for sustainable and electricity&#x2011;independent refrigeration technologies. In response to this challenge, this work proposes a novel solar&#x2011;assisted single&#x2011;effect Lithium Bromide&#x2013;Water (LiBr/H&#x2082;O) absorption refrigeration system incorporating a supersonic ejector and a triple&#x2011;layer solar thermal storage unit. The design aims to maximize energy recovery and reduce operating cost through combined thermodynamic and thermoeconomic optimization. Governing mass and energy conservation equations are established and solved using the Engineering Equation Solver (EES). Energy, exergy, and cost assessments are performed for both ejector&#x2011;assisted and conventional configurations to quantify improvements in the Coefficient of Performance (COP), exergy efficiency, and component cost rate under various solar irradiation and generator temperatures. Results reveal that ejector integration enhances COP by 12.7% and exergy efficiency by 11.3%, while reducing total investment cost by 9% compared to the baseline cycle. The optimized configuration achieves coefficient of performance of 0.74 and solar coefficient of performance of 0.58 under solar irradiation of 973&#xa0;W/m&#xb2;, confirming marked enhancements in thermodynamic efficiency, cost effectiveness, and overall system sustainability.

Two-dimensional shear-wave elastography is a practical method for assessing liver fibrosis. However, an optimal cutoff value to rule out significant fibrosis (&#x2265;F2) in metabolic dysfunction-associated steatotic liver disease remains unclear. This study aimed to determine the evidence-based rule-out cutoff through diagnostic meta-analysis. A systematic review was of MEDLINE, EMBASE, and Cochrane CENTRAL was performed through December 2025 for studies evaluating 2-dimensional shear-wave elastography with liver biopsy as the reference standard. Pooled sensitivity, specificity, and summary area under the receiver operating characteristic curve were estimated. The rule-out cutoff was defined as the highest threshold achieving pooled sensitivity &#x2265;80%. External validation was performed using an independent clinical cohort. Twenty-two studies involving 3171 adults with biopsy-proven metabolic dysfunction-associated steatotic liver disease were analyzed. The summary area under the receiver operating characteristic curve was 0.84 (95% confidence interval, 0.81-0.87), with pooled sensitivity of 79.6% and specificity of 76.0%. The rule-out cutoff of 6.6 kPa (95% confidence interval, 5.4-8.2 kPa) achieved sensitivity of 80.0% and specificity of 70.7%. At this threshold, negative predictive value exceeded 95% at prevalences of 5% and 10%. Diagnostic performance was generally preserved across subgroups but was modestly attenuated in populations with greater metabolic burden and in studies using Supersonic ultrasound platforms. External validation (n = 163) demonstrated consistent sensitivity (0.86) and specificity (0.68). Two-dimensional shear-wave elastography demonstrated good diagnostic accuracy for significant fibrosis in metabolic dysfunction-associated steatotic liver disease. A liver stiffness of 6.6 kPa can reliably rule out significant fibrosis. As 2-dimensional shear-wave elastography can be integrated into conventional ultrasound systems, it may facilitate broader implementation of fibrosis screening beyond specialized centers. PROSPERO (International Prospective Register of Systematic Reviews), CRD42024616042.