Recycling and Performance Evaluation of Recycled Concrete in Construction Engineering

The construction industry is one of the largest consumers of raw materials and a significant contributor to global waste. This study aims to assess the viability of recycled concrete as a sustainable alternative to traditional concrete in construction engineering. The paper presents a detailed methodology for the collection, preparation, and testing of recycled concrete aggregates (RCA) and the production of recycled concrete. The performance of recycled concrete was evaluated through a series of tests measuring physical properties, mechanical strength, and durability. The results showed that recycled concrete had slightly higher density and porosity due to the presence of old mortar, which also led to increased water absorption. However, these values were within acceptable ranges for construction materials. In terms of mechanical properties, recycled concrete demonstrated compressive and flexural strengths that were approximately 80-90% of conventional concrete, which is sufficient for many non-structural applications. Durability tests revealed that recycled concrete had improved resistance to chloride penetration and equivalent freeze-thaw resistance compared to conventional concrete, indicating its potential for use in environments prone to these conditions

The Impact of Shared Mobility Modes on Urban Transportation Structure: A Case Study of Megacities

Megacities face challenges like traffic congestion and environmental pollution, with traditional transportation systems struggling to cope. Shared mobility modes, such as bike-sharing and ride-hailing, offer flexible and sustainable travel options, particularly in Chinese cities. This paper, drawing on shared economy and sustainable transportation theories, analyzes the impact of shared mobility on traffic congestion, environmental outcomes, and private vehicle use in cities like Shanghai, New York, and London. The study finds that shared mobility can reduce traffic pressure and emissions, but its long-term success depends on policy support and integration with public transportation

Analysis of Time-domain Characteristics of Pavement Acceleration Under the Car moving Load

In order to study the time-domain characteristics of pavement vibration acceleration under the car moving load, the collector and the accelerometer were placed on the pavement for field testing. The results show that when the vehicle speed is 50km/h and the sampling frequency is 1kHz, the peak value and fluctuation range of road vibration acceleration are the largest. When the vehicle speed is 20km/h and the sampling frequency is 400Hz, the peak value and fluctuation range of road vibration acceleration are the smallest. With the increasing of vehicle speed or sampling frequency, the peak value and fluctuation range of road vibration acceleration at the testing point also increase. This indicates that when the vibration acceleration collection points are denser and the moving load is applied faster, the fluctuation range of the pavement vibration acceleration will be wider, and the corresponding peak values will also increase

Homogenization in the process of Urbanization

In order to solve the problem of homogenization of urban development and prevent the loss of sense of place, urban planners must have a strong sense of urban cultural identity and take consistent actions in urban renewal (upgrading of old urban areas) and development. The development of new urban areas promotes the prosperity and development of urban culture by strengthening cultural identity, preserving and innovating urban culture, integrating local cultural elements, taking into account the cultural connotation and regional uniqueness of the city, and creating a city with unique charm and strong influence

Effects of Variable-Frequency Vibration Stress on Chilling Injury and Storage Quality of Blueberries

In this study, blueberries were subjected to vibration treatments of 3 Hz (3 h), 3-4-3 Hz (3×1 h), and 4-3-4 Hz (3×1 h), then stored at 4±0.5°C and 90%-95% humidity for 20 days. Physiological indices were measured every 3 days. The results showed that blueberries in the 3 Hz fixed-frequency vibration group maintained better quality, with chilling injury occurring on the 12th day. In contrast, blueberries in the 3-4-3 Hz and 4-3-4 Hz variable-frequency vibration groups suffered more severe damage, with chilling injury appearing on the 8th day, characterized by increased color difference (ΔE) and cell membrane permeability, elevated activities of superoxide dismutase (SOD) and catalase (CAT), and decreased contents of anthocyanins and ascorbic acid (AsA), as well as reduced activity of peroxidase (POD). The study indicates that variable-frequency vibration is more likely to damage blueberries than fixed-frequency vibration, providing a basis for reducing quality loss of blueberries during transportation and storage

Assessing the impact of climatic factors on the trade performance of South African maize commodity

The maize commodity is of strategic significance to the South African economy as it is a stable commodity and therefore a key factor for food security. In recent times climate change has impacted on the productivity of this commodity and this has impacted trade negatively. This paper explores the intricate relationship between climatic factors and trade performance for the South African maize. Secondary annual time series data spanning 2001 to 2023, was sourced from an abstract from Department of Agriculture, Land Reform and Rural Development (DALRRD) and World Bank’s Climate Change Knowledge Portal. Autoregressive Distributed Lag (ARDL) cointegration technique was used as an empirical model to assess the long-term and short-term relationships between explanatory variables and the dependent variable. Results of the ARDL model show that, average annual rainfall (β = 2.184, p = 0.056), fertilizer consumption (β = 1.919, p = 0.036), gross value of production (β = 1.279 , p = 0.006) and average annual surface temperature (β = −0.650, p = 0.991) and change in temperature for previous years, (β = −0.650, p = 0.991) and the effects towards coefficient change for export volumes, (β = 0.669, p = 0.0007). In overall, as a recommendation, South African policymakers should consider these findings when developing strategies to mitigate the impacts of some of these climatic factors and implementing adaptive strategies for maize producers

Design of Early Internal Short-Circuit Fault Diagnosis and Safety Early Warning System for Lithium-ion Battery Energy Storage Systems

Lithium-ion batteries are widely adopted in electric vehicles, energy storage systems, and portable electronic devices, leading to increasing concerns about battery safety. Internal short-circuit faults, a common safety hazard in lithium-ion batteries, can potentially cause thermal runaway, fires, or even explosions. To address this issue, this study proposes a machine learning-based lithium-ion battery internal short-circuit fault diagnosis and safety alert system. This system continuously monitors key battery parameters such as voltage, current, temperature, and internal resistance, and integrates machine learning algorithms, including Support Vector Machine (SVM), to form a multi-parameter fusion fault diagnosis model capable of effectively identifying abnormal battery states

A review on vehicle routing problem with time window

Vehicle routing optimization has been the focus of logistics transportation research, because vehicle routing problem with time window(VRPTW) more in line with the real sell distribution and other real life problems, so in recent years more and more domestic and foreign scholars for more detailed models and solution methods. In order to make a systematic review of the current domestic and foreign studies, this paper summarizes and analyzed 100 studies from 2010 to 2023, and detailed the commonly used solution methods

Study on Improving the Efficiency of Civil Shipping Control Management under the Background of Digital Multi-Coordination

In today’s complex and uncertain era, civil aviation enterprises face unprecedented challenges. Digital transformation offers significant potential but also poses a severe test. They must actively embrace digital development, promote comprehensive transformation, and establish a digital multi-coordination management system to enhance efficiency, achieve transformation, and elevate civil navigation control. This paper first analyzes the necessity of improving control efficiency in this context and then proposes effective strategies to do so

Design method of electric vehicles based on the concept of sustainable development

With the improvement of global environmental awareness and the intensification of the energy crisis, electric vehicles, as an important choice for green travel, have gradually become a trend in the development of modern transportation. This paper aims to explore the design method of electric vehicles based on the concept of sustainable development, focusing on the key principles of energy saving and environmental protection, resource utilization and circular economy, user safety and comfort in the design process. The study also involves aspects such as material and technological innovation, life cycle assessment and environmental impact analysis, and proposes a set of systematic design frameworks to provide theoretical support and practical guidance for the innovative design of electric vehicles. Through a comprehensive analysis of electric vehicles, this paper provides valuable references for the industry and promotes the development of electric vehicles in a more efficient, environmentally friendly and sustainable direction. Finally, the study emphasizes the importance of green design concepts to the design of future electric vehicles, and looks forward to the potential of intelligence and technological innovation in promoting the construction of sustainable transportation systems