Search Results (84)

Port green spaces are essential protective barriers, enhancing safety and environmental resilience in high-activity port regions. Given the intensity of human activities in these areas, understanding the factors influencing the carbon sequestration capacity and ecological benefits of port green spaces is crucial for developing sustainable green ports. This study integrated field investigations and remote sensing data to estimate carbon density and carbon sequestration capacity in the Dongjiakou Port area, examining their relationship with port green space planning. The results indicated that carbon density in green spaces showed a significant negative correlation with the number of lanes in adjacent roads, where an increase in lane numbers corresponded to lower carbon density. Additionally, carbon density decreased significantly with increasing distance from the shipping center. In contrast, a significant positive correlation was observed between carbon density and distance from large water bodies, indicating that green spaces closer to large water bodies exhibited smaller carbon density. Infrastructure development in Dongjiakou substantially negatively impacted vegetation carbon sequestration capacity, with effects not reversible in the short term. However, green space enhancement efforts provided additional ecological benefits, leading to a 50.9 ha increase in green space area. When assessing carbon density in urbanizing areas, geographical influences should be prioritized. Furthermore, the long-term environmental impacts of urban expansion must be considered at the early planning stages, ensuring the implementation of proactive protective measures to mitigate potential ecological disruptions. Full article

In recent years, the storage of lithium-ion battery (LIB) containers in general cargo container yards has become an urgent operational requirement for port container terminals. To effectively control the impact range of thermal runaway (TR) incidents in LIB containers and reduce potential economic losses, it is imperative to establish appropriate isolation protocols. This study develops a mathematical–physical model of heat transfer following LIB container TR, incorporating (1) the national regulation limiting stacking height to three layers, (2) the exothermic characteristics of LIB TR, and (3) the fundamental heat transfer theory. Through detailed numerical simulations based on actual engineering scenarios, our analysis demonstrates that when (1) The TR temperature of conventional LIBs remains below 700 °C, (2) the thermal conductivity of goods in adjacent ordinary cargo containers does not exceed 10 W/(m·K). An effective isolation configuration can be achieved by (1) arranging no fewer than four ordinary cargo containers longitudinally and (2) placing no fewer than two ordinary cargo containers transversally. The methodology and conclusions presented in this study provide practical guidance for industrial applications and demonstrate significant engineering value. Full article

This study investigates the design of omnidirectional antennas, using a characteristic mode analysis (CMA), and explores two distinct feeding methods. The first method employs equal-amplitude and in-phase excitation across all ports, whereas the second method utilizes equal-amplitude excitation with a 180° phase difference between adjacent ports. Both designs achieve operating bandwidths of 2.45–2.58 GHz and 2.42–2.45 GHz, respectively, with peak gains of 4.1 dBi and 4.4 dBi at 2.45 GHz. The proposed antennas exhibited high gain and low-profile characteristics, making them well-suited for applications in wireless energy harvesting. Full article

Ports function as logistical hubs through which approximately 80% of the world’s goods are transported annually. Recent regulatory frameworks from the International Maritime Organization (IMO) and the European Union require ships and ports to adopt measures aimed at minimizing the environmental impact of port activities and mitigate climate change. These measures include investing in renewable energy generation systems to transition from fossil fuel-based energy to renewable electricity. Consequently, to meet increasing energy demands, new energy infrastructure must be developed. However, due to spatial constraints in port environments, there is a growing interest in utilizing port service areas, inner docks, and exterior/adjacent water zones for the deployment of marine renewable energy generation systems. This study applies high-resolution meteorological and oceanographic modelling—incorporating validated wave agitation models—to assess the feasibility of integrating marine renewable energy generation within port service areas. Full article

This paper presents a comparative study of land use in different regional types under the Belt and Road Initiative (BRI) through a case study of Minsk, Vientiane, and Djibouti. The BRI has created significant opportunities for economic cooperation between China and participating countries. As key instruments for advancing the BRI and fostering regional economic development, overseas industrial parks play a crucial role in attracting investment, facilitating workforce training, and promoting local infrastructure development. With the growing number of overseas industrial parks, the need for their efficient and scientifically guided development has attracted increasing scholarly attention. However, a pressing issue remains of how to formulate context-specific and scientifically grounded development plans for these parks that account for diverse regional natural conditions and economic foundations. This study examines the China-Belarus Industrial Park in Minsk, the Saysettha Development Zone in Vientiane, and the Djibouti International Free Trade Zone, using remote sensing data and the patch-generating land use simulation (PLUS) model to analyze land use changes and driving forces in these three cities from 2000 to 2020, thereby revealing regional land-use patterns and their developmental differences. The findings indicate that population density, transportation infrastructure, and topographic features are the primary driving forces behind land use changes in the areas surrounding the industrial parks, significantly influencing the expansion of construction land and the utilization patterns of adjacent land types. Moreover, variations in natural conditions and economic strategies across regions result in divergent land use changes, giving rise to distinct urbanization characteristics. The coordinated development of ports, industrial parks, and urban areas plays a vital role in advancing regional economic integration. Through quantitative analysis, this study provides theoretical support and practical guidance for the planning and development of overseas industrial parks along the BRI. It advocates for tailored development strategies that align with specific regional contexts, in order to avoid the shortcomings of one-size-fits-all policies under varying natural and economic conditions. Full article

A surface acoustic wave-based NO₂ sensor and its interface electronics, utilizing monolayered two-dimensional sensing materials, were developed for internal pollution monitoring in spacecraft. The sensor system consists of a two-port SAW delay line with monolayered graphene/MoS₂ flakes in the cavity region between two interdigital transducers, along with the interface electronics. A microheater was integrated adjacent to the sensor to maintain a stable temperature field on the sensor surface, thereby enhancing sensitivity, response/recovery times, and selectivity. The monolayered graphene/MoS₂ sensing material, with its high surface-to-volume ratio, excellent mobility, and moderate bonding force with target molecules, enables the rapid response and recovery times of less than 2.5 and 8 s, respectively—among the fastest reported in SAW gas sensor technology. The developed sensor combines the conductivity changes, the mass loading effect, and a synergistic effect that promotes carrier separation caused by a built-in potential barrier between the two monolayers, providing exceptionally high sensitivity of 578 Hz/ppm. Additionally, the sensor’s interface electronics were engineered to mitigate the effects of external factors, such as temperature and humidity, ensuring a stable and reliable performance under varying harsh conditions. Full article

The design of wideband multi-port multiple-input multiple-output (MIMO) antennas and their optimization are very important for next-generation smartphones with the increase in massive connectivity. This paper offers the design, simulation, measurement, and specific absorption rate (SAR) analysis of a Pi-shaped ten-element MIMO antenna system for use in the upper mid-band, covering LTE 46 (5.15–5.925 GHz), LTE 47 (5.855–5.925 GHz), and n102 (5.925–6.425 GHz), thus meeting a good fractional bandwidth of 32.7% with a maximum peak gain of 2.89 dBi. Hence, it is well suited for high-isolation (<−10 dB), compactness, and wideband (4.7–6.5 GHz) applications suitable for the current communication system needs. The overall size of the proposed system is 125 mm × 70 mm, with a planar dielectric material Rogers RT/5880. Designing the proposed antenna with multiple units entails the preservation of the spatial features of the antenna alongside the reduction of the mutual coupling for adjacent elements by using a decoupling structure. Due to the high accuracy of the positioning elements and precise geometric transformations, the antenna system provides high-performance analysis based on reflection coefficients, radiation patterns, and each antenna’s averaged efficiency values (76.12–91.57%). Full article

Coastal erosion hotspots frequently emerge in the downdrift zones of ports situated along open littoral drift seashores, often necessitating coastal protection measures. This study aims to evaluate the effectiveness of nearshore nourishment in mitigating coastal erosion using the downdrift zone of the Klaipėda Port (Baltic Sea) as a case study. In 2022, 79,390 m³ of sand was discharged at 2.0–3.5 depths at this site, forming an artificial sandbar parallel to the shoreline. The dynamics of the nourishment deposits were monitored for two years through beach and nearshore morphometric measurements and beach sand lithological composition sampling. Monitoring data indicated that the majority of the sand from the artificial sandbar migrated towards the subaerial coast, with minor depth variations also observed at depths of 4.0–5.6 m. Minor accretion in the nearshore was observed in regions beyond the designated nourishment area. The nearshore nourishment has successfully stabilised the subaerial coast at the discharge site for over two years, with 21.1% of the nourished sand accumulating on the subaerial coast and the shoreline position advancing seaward by an average of 10 metres. About 69.4% of the nourished sand remained at the nourishment site between the shoreline and the offshore boundary of the artificial sandbar, while approximately 9.5% was transported to the adjacent coast beyond the nourishment area. Full article

A short-circuited coupling structure (SCCS) is proposed to obtain a gain-filtering response for dual-polarized antennas. A conventional dipole is designed with two intrinsic radiation nulls. By introducing an SCCS, an additional radiation null is obtained, and the impedance bandwidth of an antenna can be further improved. Based on this design principle, two dual-polarized filtering antennas are designed for 4G and 5G wireless communication devices. The impedance bandwidth of the proposed 4G filtering antenna is 1.63–2.97 GHz (|S11| < −15 dB), with four radiation nulls at 1.1 GHz, 3.25 GHz, 3.5 GHz, and 4.0 GHz. The impedance bandwidth of the proposed 5G filtering antenna is 3.23–4.21 GHz (|S33| < −15 dB), with four radiation nulls at 1.7 GHz, 2.5 GHz, 3 GHz, and 4.6 GHz. Further, the decoupling function of the SCCS on 4G/5G MIMO antenna designs is also discussed. When introducing an SCCS, the port isolation levels of two elements between the 4G and 5G antennas, as well as the adjacent 5G antennas, can be improved by 14 dB and 6 dB, respectively. The port isolation levels of five elements between the 4G and 5G antennas, as well as the adjacent 5G antennas, can be improved by 15.2 dB and 9.5 dB, respectively. This technique could also be a potential candidate for optical antenna designs in optical front-ends and other multi-wavelength fiber lasers with microstructures. Full article

This study performed a 3D CFD analysis on a GP3 rotary engine to determine the stroke and flow characteristics and examine the thermal- and flow-related design factors’ validity. The 3D CFD analysis was performed using the CONVERGE program, utilizing the automatic grid generation function based on the 3D engine design drawing, which is suitable for a rotating rotary engine geometry. The target species and error tolerance were selected based on the GRI-Mech 3.0 full reaction mechanism to validate the reaction model and define a reasonable range of target species and error tolerances. The RNG k-ε turbulence and SAGE combustion models were also employed to analyze the four-stroke characteristics for the GP3 engine by visualizing the internal flow. The various outcomes confirmed the rotary engine’s unique characteristics and were reasonably interpreted to validate the engine design factors. In particular, the EGR phenomenon in the intake and exhaust port overlap area and the interference phenomenon in the port overlap area between adjacent cylinders are unique to the engine, and were rationally analyzed to more accurately predict the engine’s performance. The results of this study regarding the flame quenching regions indicated power and efficiency, and the emission characteristics can be used to validate the design parameters. Full article

The large-scale storage and stable supply of oil products are essential for national energy security and economic development. As the economy expands and energy demands rise, centralized storage and supply systems become increasingly vital for ensuring the efficiency and reliability of oil product distribution. However, large oil storage depots present substantial safety risks. In the event of fires, explosions, or other accidents, emergency response efforts face stringent demands and challenges. To enhance the emergency response capabilities of oil storage and transportation bases (OSTBs), this paper proposes an innovative approach that integrates the improved analytic hierarchy process (IAHP) with the Entropy Weight Method (EMW) to determine the combined weights of various indices. This approach reduces the subjective bias associated with the traditional analytic hierarchy process (AHP). The emergency response capabilities of OSTBs are subsequently evaluated through fuzzy comprehensive analysis. An empirical study conducted on an OSTB in the Zhoushan archipelago quantitatively assesses its emergency preparedness. The results show that the base excels in pre-incident prevention, demonstrates robust preparedness and response capabilities, and exhibits moderate recovery abilities after incidents. These findings provide a theoretical foundation for reducing the likelihood of accidents, enhancing emergency response efficiency, and mitigating the severity of consequences. Practical recommendations are also offered based on the results. Full article

Accurate prediction of ship traffic flow is essential for developing intelligent maritime transportation systems. To address the complexity of ship traffic flow data in the port and the challenges of capturing its dynamic spatiotemporal dependencies, a dynamic spatiotemporal model called Temporal convolutional network-bidirectional Gated recurrent unit-Pearson correlation coefficient-Graph Attention Network (TG-PGAT) is proposed for predicting traffic flow in port waters. This model extracts spatial features of traffic flow by combining the adjacency matrix and spatial dynamic coefficient correlation matrix within the Graph Attention Network (GAT) and captures temporal features through the concatenation of the Temporal Convolutional Network (TCN) and Bidirectional Gated Recurrent Unit (BiGRU). The proposed TG-PGAT model demonstrates higher prediction accuracy and stability than other classic traffic flow prediction methods. The experimental results from multiple angles, such as ablation experiments and robustness tests, further validate the critical role and strong noise resistance of different modules in the TG-PGAT model. The experimental results of visualization demonstrate that this model not only exhibits significant predictive advantages in densely trafficked areas of the port but also outperforms other models in surrounding areas with sparse traffic flow data. Full article

This article presents a symmetrical reduced-size eight-element MIMO antenna array with high electromagnetic isolation among radiators. The array utilizes easy-to-build techniques to cover the n77 and n78 new radio (NR) bands. It is based on an octagonal double-negative metamaterial split-ring resonator (SRR), which enables a size reduction of over 50% for the radiators compared to a conventional disc monopole antenna by increasing the slow-wave factor. Additionally, due to the extreme proximity between the radiating elements in the array, the modal significance (MS) method was employed to identify which propagation modes had the most impact on the electromagnetic coupling among elements. This approach aimed to mitigate their effect by using an electromagnetic barrier, thereby enhancing electromagnetic isolation. The electromagnetic barriers, implemented with strip lines, achieved isolation values exceeding 20 dB for adjacent elements (<0.023 λ) and approaching 40 dB for opposite ones (<0.23 λ) after analyzing the surface current distribution by the MS method. The elements are arranged in axial symmetry, forming an octagon with each antenna port located on a side. The array occupies an area of 0.32 λ² at 3.5 GHz, significantly smaller than previously published works. It exhibits excellent performance for MIMO applications, demonstrating an envelope correlation coefficient (ECC) below 0.0001, a total active reflection coefficient (TARC) lower than −10 dB for various incoming signals with random phases, and a diversity gain (DG) close to 20 dB. Full article

Background: This study aimed to evaluate post-operative lower limb function following second-generation mechanically aligned medial pivot (MP) TKA implantation. Standard gait analysis was performed to collect kinematic and kinetic data, which were then compared with physiological data from the literature obtained using the same evaluation methodology as the present study. The hypothesis was that this TKA would not fully restore normal knee and adjacent joint motion during walking. Methods: Our cohort comprised 15 patients consecutively enrolled from September 2019 to December 2022 who underwent primary TKA with the second-generation MP Evolution Knee System (MicroPort Orthopaedics Inc., Arlington, TN, USA). Pre-operatively and 6 months post-surgery, gait analysis during level walking was performed on all patients, as well as clinical evaluations using the Knee Society Score (KSS), the Knee Injury and Osteoarthritis Outcome Score (KOOS), and the Visual Analogue Scale (VAS). Results: The clinical scores improved significantly (p < 0.001) after surgery (pre-/post-operative KSS functional, KSS clinical, VAS, and KOOS: 51.7 ± 17.3/84 ± 18.4, 45.3 ± 16.2/74.1 ± 12.6, 6.9 ± 1.8/2.0 ± 1.9, and 33.9 ± 11.8/69.1 ± 16.5, respectively). The statistical parametric mapping (SPM) analysis between the post-operative and reference control data revealed significant differences in the initial and final 20% of the gait cycle for the rotation of the knee in the frontal and transverse planes and for the rotation of the ankle in the sagittal plane. Conclusions: This study shows that new-generation MP TKA with mechanical alignment does not fully restore normal gait biomechanics, particularly in knee rotational movements, indicating a need for improved surgical techniques and prosthetic designs. Full article

A design for a pogo-pin probe card featuring a metallic socket is proposed to eliminate signal leakage and coupling loss in a multi-port environment. The proposed metallic pogo-pin socket includes a metal wall structure between adjacent pogo pins, ensuring complete isolation. This metal wall offers an advantage in removing coupling issues between pogo pins that can occur with typical dielectric pogo-pin sockets. The designed probe card is fabricated as a prototype and verified for its performance. Measurement results using a test through line show that coupled power is minimized, providing a low-loss transmission performance of −2.14 dB to an RF chip at 50 GHz, all within a compact size. Although the dielectric spacer used to secure the pogo pins allows for some leakage, it can maintain a low coupling performance of under −15 dB in the millimeter-wave band. The prototype probe card can deliver an RF signal to a 5G circuit with a low loss of −0.7 dB at 28 GHz and −1.9 dB at 39 GHz frequency. The designed probe card is capable of transmitting multiple RF signals to the RF system without signal distortion in a multi-port environment. Full article