Search Results (343)

Environmental supply-chain governance increasingly requires firms to trace climate accountability across buyer–supplier relationships. This study examines whether downstream customer climate pressure is associated with suppliers’ green supply-chain management and value-chain carbon accountability among Chinese listed firms. We construct an exposure-weighted customer pressure measure by combining disclosed top-customer relationships with customer climate-accountability signals, and we decompose this measure into disclosure-based and non-disclosure-based components so that symbolic and substantive accountability can be separated. We then link this measure to supplier green supply-chain indicators, value-chain carbon-disclosure components, Scope 3 disclosure, environmental investment, and reported environmental performance indicators, including air emissions, water pollutant discharge, resource consumption, and environmental tax. Using firm-year panel regressions with fixed effects, alternative pressure measures, selection corrections, and extended outcome tests, we find an association between customer climate pressure and supplier value-chain disclosure. The depth of the association is concentrated where customer carbon-disclosure visibility is observed and is not separately identified in the smaller climate-only subsample, while the value-chain interaction association is positive but imprecisely estimated there. The value-chain disclosure associations are robust to a year-stratified randomization-inference placebo test. We do not find evidence that customer pressure is associated with supplier emissions, resource use, environmental investment, or environmental tax in the available matched samples. The pattern is consistent with symbolic compliance in supply-chain carbon accountability: customer disclosure visibility maps into supplier disclosure visibility, while we do not observe parallel movement in substantive environmental outcomes. The central finding is therefore that downstream customer climate pressure is associated with what suppliers disclose rather than with what they emit, shaping supplier disclosure behavior rather than substantive emission reduction. The estimates apply to supplier-year observations with disclosed and mappable listed-customer links, which we treat as the scope condition of the study rather than as an incidental data limitation. Full article

Solid fuel ramjets (SFRJs) are air-breathing propulsion systems with a high specific impulse, but their sudden expansion combustors often exhibit axially nonuniform fuel regression because of the distinct recirculation, reattachment, and downstream turbulent diffusion flame regions. However, previous studies have primarily focused on the average regression rate, with limited attention to local combustion characteristics. This study applied a photogrammetry-based three-dimensional shape reconstruction technique to obtain the post-combustion internal port geometry of a sudden-expansion SFRJ combustor burning high-density polyethylene fuel under different chamber pressure and air mass flux conditions. This geometry was employed to determine the axial distributions of the local regression rates. The analysis procedure was validated against the corresponding space–time averaged regression rate obtained from fuel mass loss, showing suitable agreement with relative errors of 1.7–5.7%. The axial distributions consistently exhibited low values in the upstream, increased rapidly in the middle region, and sustained high or gradually decreasing in the downstream. In addition, an empirical expression for the space–time averaged regression rate indicated greater sensitivity to air mass flux than chamber pressure. These results confirm that photogrammetry is an effective tool for resolving the axially nonuniform regression behavior and informing spatial insights beyond the average regression rate alone. Full article

A unique motor–syringe air control system is introduced to power a PneuNet-inspired silicone soft robotic hand. The system consists of a novel motor–syringe air drive (MSAD) pneumatic device with a crank–slider mechanism that integrates the functionalities of common medical syringes and servo motors. This novel system is integrated with pressure and flex sensors to overcome challenges encountered with using traditional compressor-powered actuation systems to achieve superior linear pressure profiles, provide precise control over soft finger movements, and minimize the noise emitted. Our soft finger design is inspired by the architecture of PneuNet pneumatic actuators and is further optimized by performing ANSYS Workbench (version 2023) simulations to considerably enhance the bending efficiency. A pressure sensor is deployed in each finger chamber for the purpose of grasping force control in terms of air pressure. Furthermore, the deployed pressure sensor in each finger chamber can also continuously monitor the air leakage, and a replenishment valve can be activated when the air leakage significantly affects (i.e., less than 95% of target pressure) the actuation to restore atmospheric pressure in the syringe chamber to restore the MSAD function. Different tests on bending and grasping (including grasping objects with various shapes) are performed to verify the performance of the proposed pneumatic actuator and the five soft fingers. Full article

The cylindrical hydrocyclone can be regarded as a special-shaped hydrocyclone comprising entirely cylindrical sections without conical sections, featuring a unique flat-bottom design combined with central discharge, which promotes substantial particle circulation flow in the separation chamber, directly affecting separation performance. A validated TFM model is employed to investigate the flow field and particle motion behavior in the cylindrical hydrocyclone. The results indicate that the distributions of tangential velocity, radial velocity, pressure, and pressure gradient in the cylindrical hydrocyclone are consistent with patterns observed in the conventional hydrocyclone. The flat-bottom design combined with the central discharge configuration of the cylindrical hydrocyclone results in two distinct axial velocity transitions in the bottom region, forming downward axial velocity flow around the air core. Accordingly, particles moving toward the spigot must pass through the internal swirling flow region, facilitating the fine particles entrained by the coarse particles to enter the internal swirling flow, reducing the misplacement of fine particles in the underflow. Simultaneously, coarse particles entrained by the internal swirling flow return to the external swirling flow region under centrifugal force, forming a substantial coarse particle circulation flow. As a result, a mass of coarse particles accumulates in the separation chamber, hindering the centrifugal settling of medium particles and resulting in an enlarged cut size and severe coarse particle misplacement. Full article

Integrating a heat exchanger (HEX) into the cooling duct of a high-power fuel-cell-based aircraft presents a critical trade-off between thermal performance and aerodynamic penalties. The present study addresses this challenge through the design and system-level analysis of a HEX integrated into the cooling duct. Developed as part of the Clean Aviation project FAME, the design features a rectangular inlet, a circular outlet, and a tilted HEX. The evaluation is performed using high-fidelity Large Eddy Simulations (LESs). The HEX is modeled with a porous media approach based on the Darcy–Forchheimer equation, while the simulations are carried out using a self-adapted version of the pisoFoam solver, termed pisoTempFoam, to account for heat transfer. The study reveals that while component-level design choices, such as a straight inlet and tilted HEX configuration, successfully mitigate local flow separation and duct-induced losses, a critical system-level performance issue emerges. The analysis demonstrates that the cooling duct design, when subjected to realistic operational conditions, generates the high pressure head to overcome the resistance of the HEX. The external aerodynamic analysis also indicates that the HEX resistance is a critical factor, and without overcoming it the system fails to capture the required air mass flow rate, compromising thermal management. The findings highlight the necessity to optimize the design, by an adapted duct shape or an auxiliary fan, to overcome the HEX-induced pressure drop. The porous media approach is thereby validated as an effective tool for rapid system-level design analysis, despite its inherent limitation in capturing detailed downstream turbulence. Full article

High-speed train aerodynamics have mainly been improved by passive design methods, such as streamlined noses, local fairings, and surface smoothing. These methods have achieved clear benefits, but several important aerodynamic problems remain difficult to solve by geometry optimization alone. Open-air drag is still affected by tail flow separation, base-pressure recovery, and disturbances around bogies and the underbody; crosswind safety is influenced by unsteady leeward-side separation and wake asymmetry; slipstream behavior depends on wake vortices, boundary-layer development, and complex near-ground underbody flow; and tunnel-related pressure transients arise from compression-wave generation, propagation, and reflection. These coupled effects mean that one fixed train shape cannot perform optimally in all operating conditions. For this reason, this review proposes that active flow control (AFC) should not be regarded only as a drag-reduction or stability-improvement technique for high-speed trains. Instead, it should be understood as a mission-adaptive aerodynamic control framework, in which different control actions are used for different operating scenarios. This paper first clarifies that passive optimization is increasingly subject to diminishing returns under multi-objective and engineering constraints. It then reviews AFC studies on drag reduction, base-pressure recovery, wake and slipstream control, underbody flow conditioning, crosswind mitigation, and tunnel pressure-wave suppression. Related AFC studies on bluff bodies, road vehicles, and other separated flows are included only when their physical relevance to trains is clear. The review further distinguishes gross aerodynamic improvement from net energy gain and identifies actuator power, durability, maintainability, acoustic impact, validation level, and full-scale transferability as decisive feasibility factors. Current research is still dominated by open-loop numerical studies with simplified actuation. Future work should therefore move toward multi-objective, closed-loop, energy-aware, sensor–actuator-integrated, and explainable machine-learning-assisted AFC. The main message is that the next step in train aerodynamics is not simply a better fixed shape, but a control-enabled train that can selectively redistribute aerodynamic authority across its mission profile. Full article

The interaction between crossflows from sprinkler nozzles and airflow is crucial for engineering applications, particularly affecting the efficiency of sprayed areas. This study investigates the deformation of a continuously injected conical water spray subjected to horizontal airflow, using a planar laser imaging method as a visualisation technique. Experiments were conducted in a wind tunnel at a constant water pressure of 0.2 MPa and four airflow rates (0.1, 0.2, 0.4, and 0.6 m³·s⁻¹) to systematically vary the air-to-water momentum ratio. A grayscale-based analysis method was developed using a per-pixel Look-Up Table (LUT), enabling indirect assessment of droplet concentrations and spray structure. This approach allowed for a detailed examination of changes in the spray cone shape under flowing air. By assessing the water spray across three vertical planes intersecting the spray cone, it became possible to calculate lateral area and cone volume at different air-to-water mass flow ratios. The spray formation region exposed to airflow exhibited larger cone volumes than those with minimal airflow. The changes in apparent spray angles for the tested nozzles were determined to characterize the cone shape. The apparent spray angle varies systematically with the air-to-water mass flow ratio, confirming the dominant role of aerodynamic forces. These findings improve the understanding of spray behavior under crossflow and provide a basis for validating numerical models of air–water interactions. Full article

Air knives are extensively employed in many cold rolling or tin plate production lines for drying purposes. Generally, these systems are oversized, resulting in excessive energy consumption, a consequence of insufficient understanding of their performance. Considering this deficiency, an empirical exploration was initiated to analyze the functionality of an air knife oriented perpendicularly to a given surface. Given the scarcity of information within the current body of literature, particular emphasis was placed on the regions affected by the finite dimensions of the device. Impingement pressure distributions were measured at the midspan plane and planes parallel to the midspan but extending beyond the projection of the air knife. The midspan impingement pressure profile aligned with the established bell-shaped distribution, whereas the outcomes beyond the air knife’s projection conformed to an analytically fitted similarity principle. Consequently, the mathematical formulations introduced in this study facilitate the mapping of the impingement pressure within the whole impingement plane, encompassing areas influenced by the finite length of the air knife, thereby representing the innovative contribution of this research. Full article

Background: Air pollution, antimicrobial use, and population ageing are increasingly recognised as co-occurring pressures shaping population health. This study explores their ecological association with mortality patterns in the province of Messina (Southern Italy), within a One Health-informed framework. Methods: An ecological analysis was conducted using district-by-year data (2015–2024), integrating environmental monitoring (PM₁₀, PM_2.5, NO₂, O₃), outpatient antibiotic consumption, and cause-specific mortality rates. Multivariable regression models were used to assess associations between exposures and mortality outcomes. A post-2020 indicator was included to account for COVID-19-related disruption. Results: Marked geographic variability in pollutant concentrations was observed, with higher levels in urban-industrial districts. Infectious disease mortality increased from 13.8 to 44.6 per 100,000 inhabitants between the pre-pandemic and post-pandemic periods. In Poisson regression models, particulate matter showed a small and non-significant association with respiratory mortality (RR = 1.02, 95% CI: 0.89–1.18), while antibiotic consumption was not independently associated with mortality (RR = 0.99, 95% CI: 0.94–1.05). The post-2020 period was associated with higher mortality estimates (RR = 1.15, 95% CI: 0.72–1.83), although with wide confidence intervals. Conclusions: The findings suggest the co-occurrence of environmental, demographic, and pharmaceutical pressures within the same territories, rather than demonstrating formal synergistic interaction. The observed post-pandemic increase in mortality highlights the importance of accounting for COVID-19-related disruption. These results should be interpreted as exploratory, given the ecological design and limited sample size, but support the need for integrated surveillance approaches within a One Health perspective. Full article

This study develops and applies an integrated methodology that combines deep learning-based computer vision and spatial statistics to automate the large-scale identification and analysis of morphological features in vernacular courtyard dwellings. Focusing on Liangshuaixiu dwellings in Wu’an, southern Hebei, we trained an HRNetV2 semantic segmentation model on high-resolution satellite imagery to identify and extract contours for 134,280 courtyard spaces. Core morphological parameters (area, orientation) were calculated and analyzed using GIS spatial statistics and the geographic detector model. The results show that (1) the computer vision pipeline achieved efficient recognition with satisfactory accuracy (~10% mean error); (2) spatial autocorrelation and hotspot analysis revealed distinct regional patterns, including a west–east increase in average courtyard area; and (3) geographic detector analysis demonstrated that courtyard morphology is shaped by complex interactions between natural and socio-economic factors. While average area and orientation were primarily governed by climate (air pressure, wind, temperature) and topography (elevation), diversity and internal variation were strongly influenced by nonlinear interactions, particularly between natural factors (e.g., wind–aspect) and between natural and human factors (e.g., population–climate). This work provides a scalable, data-driven framework for the quantitative spatial analysis of vernacular architectural heritage, advancing the understanding of building morphology as an outcome of coupled human–environment systems. Full article

Rotor machining errors strongly influence the air-film pressure distribution of aerostatic spindles and fundamentally limit performance enhancement. However, existing studies rarely provide a comprehensive statistical characterization based on measured manufacturing errors. To address this gap, a multi-scale modeling framework based on harmonic analysis of form errors is developed. Measured surface topography data from a batch of rotors are decomposed to establish a harmonic statistical model, which is then incorporated into a modified Reynolds equation together with macro-scale and micro-scale error components. The static performance of the aerostatic spindle is subsequently analyzed. Results show that low-order harmonics (1st–5th) dominate cylindricity errors, with amplitudes following a log-normal distribution. The statistical bounds are described by 3σ envelopes. When the eccentricity ε exceeds 0.3, barrel-shaped errors reduce the load capacity by more than 15%, whereas waist-drum-shaped errors exhibit a self-stabilizing tendency under small deviations. Performance degradation can be partially mitigated by adjusting the supply pressure and orifice diameter. This study addresses the research gap in understanding the impact of measured manufacturing errors on aerostatic spindle performance and provides a quantitative basis for tolerance allocation and performance optimization. Full article

With the development of manufacturing towards stricter precision requirements and increasingly complex geometric shapes, dimensional accuracy has become a key factor affecting precision engineering components used in many industries. Effective cooling and lubrication methods have always been a meaningful way to improve the surface quality of cutting materials. Minimum-quantity lubrication technology mixes compressed air with cutting fluid, produces a spray at ambient temperature, and guides these droplets to the cutting area under the action of high-pressure air to promote penetration into the contact area between the tool, workpiece, and chip. Minimum-quantity lubrication can be used to increase cutting speed, cool workpieces, improve workpiece quality, and significantly reduce the pollution caused by cutting fluid to the environment. However, minimum-quantity lubrication technology still cannot meet the requirements of sustainable machining in cutting processes. A test device platform for milling 6030 aluminum alloy with minimal quantity lubrication was established, and different cooling methods were used to analyze the effect on surface roughness. The spindle speed n, feed rate f, and cutting depth a_p are selected as optimization variables, with surface roughness as the optimization objective. Single-factor experiments were conducted to determine the optimal range for these variables. Subsequently, a model was constructed using the response surface methodology and solved using Design-Expert software. The interaction effects of spindle speed, feed rate, and depth of cut on surface roughness were analyzed. Additionally, genetic algorithms were employed to optimize cutting process parameters for the best combination. The results demonstrated that by combining Response Surface Methodology (RSM)and genetic algorithms, when the spindle speed n was 2520 r/min, the feed rate f was 48 mm/min, and the depth of cut a_p was 0.08 mm, the actual surface roughness after milling reached 0.148 µm, representing a 74.57% reduction compared to the initial surface roughness. This research method provides a theoretical foundation and technical support for optimizing minimal quantity lubrication (MQL) cutting processes. Full article

To meet the integrated design requirements of the belly-mounted air-breathing vehicle forebody and inward-turning inlet, an integrated design method for the dual-stage compression inward-turning inlet (DCII) based on a conical forebody is developed, to facilitate subsequent splitter regulation. The parameters of a specific entrance in the forebody flowfield are adopted as the input parameters for the internal conical flowfield; combined with streamline tracing technology and the “dual-waverider” concept, an integrated configuration is generated. Numerical simulation results indicate that, under viscous conditions, the shock structure at the symmetry plane of Configuration 1 deviates from the design expectations. This discrepancy arises from the convergence of low-energy flow and the boundary layer. Configuration 2 was proposed by modifying the forebody shape to mitigate low-energy boundary layer flow convergence, achieving a mass flow coefficient of 0.95, a total pressure recovery coefficient of 0.51, and an outlet total pressure rise ratio of 26.14 at the design point (Ma = 6.35). At off-design points, Configuration 2 still maintains a high total pressure recovery coefficient while retaining both a high outlet pressure rise ratio and mass flow coefficient. Full article

This systematic review synthesizes passive and passive-first cooling strategies for greenhouses in hot–arid climates, organizing evidence across four domains: Airflow & Ventilation, Shading & Radiative Control, Thermal Storage & Ground Coupling, and Structural Design & Geometry. Drawing on the project corpus, we analyze 10–13 distinct techniques including ridge and side natural ventilation, windcatchers and solar chimneys, external shade nets, NIR-selective and transparent radiative-cooling films, and dynamic PV shading; earth-to-air heat exchangers (EAHE/GAHT), rock-bed sensible storage, phase-change materials (PCMs), and sunken or buried envelopes; as well as roof slope and shape, span number, and orientation. Across studies, cooling outcomes are reported as peak or daytime indoor air temperature reductions, defined relative either to outdoor conditions or to a control greenhouse, with the reference frame and temporal aggregation specified in the synthesis. Typical outcomes include ≈3–7 °C daytime reduction for optimized ventilation, ≈2–4 °C for shading and spectral covers while preserving PAR, ≈5–7 °C intake cooling for EAHE with winter pre-heating, and up to ≈14 °C peak attenuation for rock-bed storage under favorable conditions. Structural choices consistently amplify these effects by sustaining pressure head and limiting thermal heterogeneity. Performance is strongly context-dependent—governed by wind regime, diurnal amplitude, dust and UV exposure, and crop-specific light and temperature thresholds—and the most robust results arise from stacked, site-specific designs that combine skin-level radiative rejection, buoyancy-supportive geometry, and ground or latent buffering with minimal active backup. Smart controllers that modulate vents, shading, and targeted fogging or fans based on VPD or temperature differentials improve stability and reduce water and energy use by engaging actuation only when passive capacity is exceeded. We recommend standardized composite metrics encompassing temperature moderation, humidity stability, PAR availability, and water and energy use per unit yield to enable fair cross-study comparison, multi-season validation, and policy adoption. Collectively, the synthesized techniques provide a practical palette for improved greenhouse climate management under hot and arid conditions. Full article

Robotic grippers play a crucial role in pick-and-place tasks, as their performance directly affects the robot’s operational efficiency, stability, and safety. In industrial applications, such as coal gangue sorting, the target objects have irregular shapes and sharp surfaces, which pose challenges to the gripper’s grasping ability. To solve these problems, an adaptive under-actuated gripper based on rope control is designed. The gripper is simple to control and combines the excellent features of both rigid and flexible grippers. To analyze the characteristics of the gripper, both mathematical analysis and holding force experiments are conducted. The results show that the gripper can generate a greater holding force when grasping larger objects with a constant input air pressure. Furthermore, irregularly shaped testing objects, including coal lumps and ores, are selected to conduct grasping experiments. The gripper achieves a 100% grasping success rate with a load of up to four times the object’s weight suspended beneath it and shows the ability to reliably grasp irregularly shaped objects in high-speed pick-and-place tasks with a payload of four times the object’s weight. Meanwhile, the gripper has a passive anti-collision ability due to the special outer contour of the distal finger when subjected to unexpected, sudden force. Full article