Ecological effect of urban spatial expansion in river valleys: A case study in the main urban area of Lanzhou City

[Objective] The ecological effect of urban spatial expansion is the key problem of human-environment relationship in the process of urbanization. It is of great significance to explore the complex scientific problem of ecological effect caused by urban spatial expansion from multiple angles to promote the sustainable and high-quality development of urban and ecological space. [Methods] Taking the main urban area of Lanzhou City in China as an example, this study calculated the scale, intensity, and landscape pattern indices of urban spatial expansion in 1995, 2005, 2015, and 2020 to reflect the spatiotemporal variation characteristics of urban spatial expansion in the city from 1995 to 2020, and divided the research area into 12184 grids. Using the spatial principal component analysis method, atmospheric radiation transfer equation method, and revised ecosystem service value estimation model, this study analyzed the ecological risk effect, heat island effect, and ecosystem service effect of urban spatial expansion from various angles, and discussed the impact of natural environment conditions on the ecological effect of urban spatial expansion of cities in river valleys. [Results] The results show that from 1995 to 2020, the scale and intensity of urban expansion in Lanzhou City have increased, the fragmentation of urban landscape has decreased, urban expansion has mainly occurred in the western and northern parts of the city, and the urban expansion mode has changed from group expansion to leaping expansion. The overall ecological risk effect and heat island effect in the city have shown a weakening trend, but a rising trend was observed in the river valley, and the overall pattern of effects has been characterized by high in the valley and low at the peripheries. There is a slight improvement in the ecosystem service effect, which mainly shows that the ecosystem service value in the surrounding areas of the river valley has improved significantly, and some areas in the built-up area have changed from low-value area to medium-value area. Urban expansion negatively affects the natural substrates of the region, while the natural substrates also affects the scale, direction, and mode of urban expansion. Coordinating the relationship between the two is essential for the sustainable and harmonious development of human beings and nature. [Conclusion] The research framework of ecological effects of urban spatial expansion was constructed from multiple perspectives. Urban spatial expansion has a significant impact on ecological risk, heat island, and ecosystem service effects at the grid scale, which provides a new way of quantitative visualization of the dynamic relationships between urban evolution and ecological environment

Molecular Identification of Multidrug-Resistant Campylobacter Species From Diarrheal Patients and Poultry Meat in Shanghai, China

Emerging resistance to the antimicrobial agents of choice for treatment of thermophilic Campylobacter infections is becoming a serious threat to public health. In this study, 548 Campylobacter (372 C. jejuni and 176 C. coli) isolates from diarrheal patients and poultry meat were subjected for antibiotic susceptibility analysis to ciprofloxacin, tetracycline, gentamicin, erythromycin and clindamycin. Among them, 151 Campylobacter (32 C. jejuni and 119 C. coli) were identified as multidrug resistant isolates. PFGE analysis was performed on the 151 multidrug resistant isolates to determine their genetic relatedness, and 103 PFGE genotypes were determined. Some isolates from both human and chicken belonged to identical genotypes, indicating these clones might be able to spread between human and chicken. Antibiotic resistant genes of the 151 isolates were identified. The numbers of isolates carried tet (O), aadE, ermB, and aadE-sat4-aphA were 148 (98%), 89 (58.9%), 31 (20.5%), and 10 (6.6%), respectively. Almost all (n = 150, 99.3%) had gyrA mutation at codon 86. And the 23s rRNA A2075G point mutation was found in 56 (37.1%) isolates. Gene mutations at the cmeR-cmeABC intergenic region may lead to the activation of CmeABC multidrug efflux pump, and in this study novel sequence types of the intergenic region were identified in both C. jejuni and C. coli. This study determined the genetic prerequisites for antibiotic resistance of multidrug resistant Campylobacter isolates from diarrheal patients and poultry meat in Shanghai, China

Review of advanced road materials, structures, equipment, and detection technologies

As a vital and integral component of transportation infrastructure, pavement has a direct and tangible impact on socio-economic sustainability. In recent years, an influx of groundbreaking and state-of-the-art materials, structures, equipment, and detection technologies related to road engineering have continually and progressively emerged, reshaping the landscape of pavement systems. There is a pressing and growing need for a timely summarization of the current research status and a clear identification of future research directions in these advanced and evolving technologies. Therefore, Journal of Road Engineering has undertaken the significant initiative of introducing a comprehensive review paper with the overarching theme of “advanced road materials, structures, equipment, and detection technologies”. This extensive and insightful review meticulously gathers and synthesizes research findings from 39 distinguished scholars, all of whom are affiliated with 19 renowned universities or research institutions specializing in the diverse and multidimensional field of highway engineering. It covers the current state and anticipates future development directions in the four major and interconnected domains of road engineering: advanced road materials, advanced road structures and performance evaluation, advanced road construction equipment and technology, and advanced road detection and assessment technologies

Effect of different additives on the hydrogen storage properties of the MgH 2-LiAlH 4 destabilized system

The hydrogen storage properties of the MgH2-LiAlH4 (4 : 1) composite system with and withoutadditives were studied. 5 wt.% of TiF3, NbF5, NiF2, CrF2, YF3, TiCl3?1/3AlCl3, HfCl4, LaCl3, CeCl3,and NdCl3, respectively, was added to the MgH2-LiAlH4 (4 : 1) mixture, and their catalytic effect wasinvestigated. Temperature programmed desorption results show that addition of metal halides to theMgH2-LiAlH4 (4 : 1) composite system improves the onset desorption temperature. The hydrogendesorption properties of metal halide-doped MgH2-LiAlH4 (4 : 1) composites were also improved ascompared to the undoped MgH2-LiAlH4 (4 : 1) composite. Furthermore, the activation energy andthe change in enthalpy in the doped and undoped composite were measured by differential scanningcalorimetry. In addition, the reaction pathway of the MgH2-LiAlH4 (4 : 1) composite system and themechanisms that work in this composite during the de/re-hydrogenation process were determined byX-ray diffraction.\u3

Improved hydrogen storage properties of MgH2 doped with chlorides of transition metals Hf and Fe

The effects of HfCl4 and FeCl3 addition on the de/rehydrogenation properties of MgH2 were investigated. Both HfCl4 and FeCl3-doped MgH2 samples started to released hydrogen at about 270 °C, a decreased of about 70 °C and about 140 °C compared to as-milled and as-received MgH2, respectively. In terms of the desorption kinetics, the HfCl4-doped MgH2 sample showed significant improvement, with 6.0 wt.% hydrogen released within 10 min at 300 °C, while the FeCl3-doped MgH2 and undoped MgH2 samples released 3.5 and 0.2 wt.% hydrogen, respectively, under the same conditions. In terms of the absorption kinetics, 5.5 wt.% hydrogen was charged at 300 °C under 3.0 MPa hydrogen in 1 minute for the HfCl4-doped MgH2 sample, while 4.8 wt.% was absorbed by the FeCl3-doped MgH2 sample, compared to just 3.0 wt.% hydrogen for the undoped MgH2 sample under the same conditions. From the Arrhenius plot based on isothermal dehydrogenation kinetics at different temperatures, the apparent activation energy of as-milled MgH2 is calculated to be 166 kJ/mol, and this value is reduced by 64 and 36 kJ/mol after doping with HfCl4 and FeCl3, respectively. A cycling study of dehydrogenation at 300 ºC shows that the hydrogen capacity of the HfCl4-doped MgH2 sample was maintained at about 6 wt.% after 10 cycles. Based on the X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy examinations, we believe that the significant improvement of MgH2 sorption properties in the doped samples is due to the catalytic effects of in-situ generated metal species and MgCl2 that were formed during the dehydrogenation process

Improved Repetitive Control for an LCL-Type Grid-Tied Inverter with Frequency Adaptive Capability in Microgrids

Repetitive control (RC), which can track any periodic signal with a known integer period with zero steady-state error, is widely used for current control of grid-tied inverters in microgrids. However, the inherent one fundamental period time delay, leads to poor dynamic performance. Furthermore, the performance of conventional RC (CRC) will degrade when operating at a high variation grid frequency. Therefore, this paper proposes a frequency adaptive improved RC (FA-IRC) for grid-tied inverters. The improved RC (IRC) consists of a repetitive controller with a modified internal model filter, plus a proportional controller. In comparison to the CRC, the IRC has a good dynamic response, because it provides a higher gain and a wider bandwidth at the resonant frequency. Moreover, to achieve the frequency adaptability of the IRC, a fractional delay, based on a finite impulse response (FIR) filter, is built into the IRC system, to ensure that the resonant frequency of the IRC is approximately equal to the actual grid frequency and harmonic frequency. Stability analysis and characteristic analysis of the FA-IRC system are reported in this paper. Simulations are conducted, to demonstrate the validity of the proposed method

Design and Acceleration of Field Programmable Gate Array-Based Deep Learning for Empty-Dish Recycling Robots

As the proportion of the working population decreases worldwide, robots with artificial intelligence have been a good choice to help humans. At the same time, field programmable gate array (FPGA) is generally used on edge devices including robots, and it greatly accelerates the inference process of deep learning tasks, including object detection tasks. In this paper, we build a unique object detection dataset of 16 common kinds of dishes and use this dataset for training a YOLOv3 object detection model. Then, we propose a formalized process of deploying a YOLOv3 model on the FPGA platform, which consists of training and pruning the model on a software platform, and deploying the pruned model on a hardware platform (such as FPGA) through Vitis AI. According to the experimental results, we successfully realize acceleration of the dish detection using a YOLOv3 model based on FPGA. By applying different sparse training and pruning methods, we test the pruned model in 18 different situations on the ZCU102 evaluation board. In order to improve detection speed as much as possible while ensuring detection accuracy, for the pruned model with the highest comprehensive performance, compared to the original model, the comparison results are as follows: the model size is reduced from 62 MB to 12 MB, which is only 19% of the origin; the number of parameters is reduced from 61,657,117 to 9,900,539, which is only 16% of the origin; the running time is reduced from 14.411 s to 6.828 s, which is only less than half of the origin, while the detection accuracy is decreased from 97% to 94.1%, which is only less than 3%

Enhancing medical image segmentation with a multi-transformer U-Net

Various segmentation networks based on Swin Transformer have shown promise in medical segmentation tasks. Nonetheless, challenges such as lower accuracy and slower training convergence have persisted. To tackle these issues, we introduce a novel approach that combines the Swin Transformer and Deformable Transformer to enhance overall model performance. We leverage the Swin Transformer’s window attention mechanism to capture local feature information and employ the Deformable Transformer to adjust sampling positions dynamically, accelerating model convergence and aligning it more closely with object shapes and sizes. By amalgamating both Transformer modules and incorporating additional skip connections to minimize information loss, our proposed model excels at rapidly and accurately segmenting CT or X-ray lung images. Experimental results demonstrate the remarkable, showcasing the significant prowess of our model. It surpasses the performance of the standalone Swin Transformer’s Swin Unet and converges more rapidly under identical conditions, yielding accuracy improvements of 0.7% (resulting in 88.18%) and 2.7% (resulting in 98.01%) on the COVID-19 CT scan lesion segmentation dataset and Chest X-ray Masks and Labels dataset, respectively. This advancement has the potential to aid medical practitioners in early diagnosis and treatment decision-making

Changes in tannin and saponin components during co-composting of Camellia oleifera Abel shell and seed cake.

This study investigated the co-compost product of the shell and seed cake of Camellia oleifera Abel, which is a small evergreen tree in the family Theaceae. Tannin and saponin contents in compost samples at different time-points and their compositional changes, as well as their relationships with nutrients and compost maturity, were analyzed using an UPLC-triple-TOF/MS system. Our results showed that tannins in the compost samples mainly consisted of 11 phenolic acid compounds, of which four small-molecule phenolic acid compounds were found in low contents. Saponins mainly consisted of five saponin aglycones (A, B, C, D, E) and four of their derivatives in C. oleifera. Microbially secreted enzymes converted the large-molecule phenolic acid compounds into small-molecule compounds and their derivatives, while saponins were decomposed into saponin aglycones. Contents of tannin and saponin had correlations with the C/N ratio, germination index (GI), and the Solvita maturity index. After composting, the content of tannin was reduced to less than 1%, and the content of saponin was not more than 2%. And compost products were safe