In the present paper, a new Integer Linear Programming (ILP) formulation is proposed for a general Multi-Day Container Drayage Problem (MDCDP) that consists in assigning trucks to container transportation tasks during...
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In the present paper, a new Integer Linear Programming (ILP) formulation is proposed for a general Multi-Day Container Drayage Problem (MDCDP) that consists in assigning trucks to container transportation tasks during several days. The model describes real-world problems taking their particular issues into account: different types of tasks, different types of containers, a heterogeneous fleet of trucks, the rest periods of drivers and so on. After a review of the state-of-the-art about the Container Drayage Problem (CDP), the MDCDP is presented and modeled as an integer programming problem. This new formulation is an improvement of a previously published formulation: it considers a more realistic objective function and fixed rest periods of drivers. As a consequence, the number of variables is quite reduced and so the new model can be more easily solved with standard solvers. Finally, computational tests on randomly generated instances are presented in order to illustrate the benefits of the new ILP formulation. In particular, it turns out that computational times for the new model are an order of magnitude lower than the previous formulation.
Modal analysis of mechanical systems and structures is a powerful tool for the assessment of vibrational behavior. Dynamical mechanical systems per their intention are used in a vast range of configurations and the vi...
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Synchronous reluctance (REL) machines attract increasing attention in recent years, mainly due to the merits of cost-saving, high-efficiency, low-maintenance and high-reliability. For industrial mass production, the d...
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Synchronous reluctance (REL) machines attract increasing attention in recent years, mainly due to the merits of cost-saving, high-efficiency, low-maintenance and high-reliability. For industrial mass production, the development of machines with a series of power ratings is of great demand. To this purpose, a detailed design of one machine is usually accomplished first, then a design of similar machines but different ratings are achieved by geometry scaling. This paper aims to investigate the scalability of the REL machines, taking into account the electromagnetic behavior and thermal performance. Analytical equations are presented to describe the scaling law, and the scaling factors for various parameters are studied. The scalability analysis is carried out in terms of linear and saturated situations, and additionally, the constant-temperature-rise conditions. At last, these analyses are verified by finite element simulations with various REL machine models.
It is very important to improve and secure durability of reinforced concrete (RC) building and housing, in order to extend the service life of it. In this study, these were studied experimentally that the contribution...
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Optimal use of steel slag and Cathode Tube Rays (CRT) as alternative materials in the construction of roads can help reduce the demand for natural aggregates. The purpose of this study is to determine the potential of...
Optimal use of steel slag and Cathode Tube Rays (CRT) as alternative materials in the construction of roads can help reduce the demand for natural aggregates. The purpose of this study is to determine the potential of aggregate mixtures consisting of steel slag as coarse aggregate and CRT glass as fine aggregate. These two materials were used as a replacement for granite. Samples were created by replacing granite with steel slag content of 30, 40, 50, 70 and 85%, respectively. While the percentage for CRT glass was set at 15% relative to total sample weight. Several laboratory tests such as Los Angeles Abrasion Value (LAAV), compaction test and Unconfined Compression Strength (UCS) were conducted. The results show that the mixture has sufficient durability, abrasion and strength to be used as aggregates replacements for the road base layer. Furthermore, the results of the UCS tests show that the strength performance of the mixture is significantly increased through the higher percentage of steel slag replacement in the mixture. In summary, both steel slag and CRT glass can be used as alternative materials for aggregate replacement in the construction of road base pavement.
Air pollution disproportionately affects socially disadvantaged populations. Our study bridges the existing gap in quantifying mobility-based exposure and its associated disparity issues. We combined the granular mobi...
Air pollution disproportionately affects socially disadvantaged populations. Our study bridges the existing gap in quantifying mobility-based exposure and its associated disparity issues. We combined the granular mobility of over 500,000 unique anonymized users daily and hyperlocal air pollution data in 100 × 100-m grid cells to quantify disparities in particulate matter exposure in a racially diverse and dense urban area of New York City. Our approach advances the study of exposure and its disparity from individualized exposure tracking to a population-representative scale. We observed apparently different spatial patterns between personal exposure and exposure disparities, noting that people from Hispanic-majority and low-income neighborhoods were those most severely and disproportionately exposed to fine particulate matter (PM2.5) pollution. We reveal that race and ethnicity are much stronger indicators of exposure disparity than income. Our study further demonstrates that within-group variation contributes a major portion to exposure disparities, suggesting more granular mitigation plans are needed to target high-exposure individuals from socially disadvantaged groups in addition to generic air quality improvement.
The Waste-to-Energy Multi-generation system provides a feasible distributed waste recycling and energy saving solution for green buildings. However, the fluctuations in electricity demands and dynamic built environmen...
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Fangzhu, which has been lost for thousands of years, is an ancient device for water collection from air;its mechanism is unknown yet. Here we elucidate its possible surface-geometric and related physical properties by...
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