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The aim of this paper is to investigate the sediment and pollution profiling and particle size distribution with depth within permeable paving structures, both with and without a geotextile.

Test rigs set up in an earlier pilot study were used for four separate but linked studies. Street dust was applied to rigs C and D to determine the retention of sediments. Heavy metals together with street dust were applied to rig A and B (previously control rigs) to determine the effect of sediment on the pollution removal capabilities of the test rigs. Following the application of sediment, rigs A and B were carefully taken apart to determine pollution profiles and particle size distributions.

The findings reveal that sediment does have an effect on the metal removal capabilities of permeable paving systems, but there was minimal difference between the rigs with a geotextile and without. Pollution profiling within the test rigs identified that the greatest concentration of metals was in the surface sediment and that both rigs removed similar percentages but the concentrations of metals were distributed differently. It was also found that after between 10 and 15 years of sediment application paving rigs began to “block” causing reduced infiltration rates. Unfortunately it is difficult to explain the variations of particle size distributions found with depth in the paving structure. It had been expected to find progressively higher proportions of finer material with depth. However, the reverse was true, with a higher proportion of fines in the sediment applied to the surface and a progressive increase in the proportion of coarse material with depth

The conclusions confirm the effects of sediment within a permeable paving structure and indicate the loading at which the infiltration rates become affected. These results may help to determine a maintenance programme, however this would require further research.

The paper provides a comparative study on pollution and sediment profiling within a permeable paving structure both with and without the inclusion of an upper geotextile. It provides valuable insight into the amount of sediment on paving before it becomes blocked. The methodology and results reported in this research could be used for further studies to provide more evidence as to whether the inclusion of an upper geotextile is beneficial.

To evaluate and optimize asphalt paving operations taking place in the reconstruction project of Interstate 74 in the USA using simulation.

Data collected during construction was used to determine useful probabilistic density functions for the activities duration and to validate a developed simulation model. Upon validation, the developed model was used to study the impact of resources on the flow of operations, and on the cost‐effectiveness of the construction process.

The developed simulation model was successful in simulating the paving operation and its accuracy was acceptable compared to field measurements. Based on the results of a sensitivity analysis of the critical resources, multiple factors were identified in the decision‐making process to ensure that all aspects of the operation were considered. For the conditions pertinent to this construction site, 30 trucks, one paver, and two rollers are recommended. Using this set of resources results in a prompt and effective execution of the construction process.

The developed model is applicable only to asphalt paving operations. The predictive capability of the developed model has not yet been investigated.

Implementation of the presented model in practical applications can be accomplished by conducting short training courses. This will provide personnel with flexibility in addressing project‐specifics conditions and limitations. If this approach is not feasible, production charts may be developed to easily determine the optimum resources that should be used given specific time constraints and quantity, issues.

The presented methodology has great potential to optimize resources and production rates in similar asphalt paving operations. Moreover, benefits of simulation would be maximized if it was used during the planning phase, as it will affect equipment orders and material shipments.

Looks at pavings and how they contribute to the character of villages, towns and cities. Surveys the history of pavings from Roman times, and discusses the different types of paving which can be found. Concludes with an outline of legal controls and planning policies.

In cities with high density, heat is often trapped between buildings which increases the frequency and intensity of heat events. Researchers have focused on developing strategies to mitigate the negative impacts of heat in cities. Adopting green infrastructure and cooling pavements are some of the many ways to promote thermal comfort against heat. The purpose of this study is to improve microclimate conditions and thermal comfort levels in high-density living conditions in Seoul, South Korea.

This study compares six design alternatives of an apartment complex with different paving and planting systems. It also examines the thermal outcome of the alternatives under normal and extreme heat conditions to suggest strategies to secure acceptable thermal comfort levels for the inhabitants. Each alternative is analyzed using ENVI-met, a software program that simulates microclimate conditions and thermal comfort features based on relationships among buildings, vegetation and pavements.

The results indicate that grass paving was more effective than stone paving in lowering air temperature and improving thermal comfort at the near-surface level. Coniferous trees were found to be more effective than broadleaf trees in reducing temperature. Thermal comfort levels were most improved when coniferous trees were planted in paired settings.

Landscape elements show promise for the improvement of thermal conditions because it is much easier to redesign landscape elements, such as paving or planting, than to change fixed urban elements like buildings and roads. The results identified the potential of landscape design for improving microclimate and thermal comfort in urban residential complexes.

The results contribute to the literature by examining the effect of tree species and layout on thermal comfort levels, which has been rarely investigated in previous studies.

Arbitrary constraints might be included into the problem domain in many engineering applications, which represent specific features such as multi-domain interfaces, cracks with small yield stresses, stiffeners attached on the plate for reinforcement and so on. To imprint these constraints into the final mesh, additional techniques need to be developed to treat these constraints properly.

This paper proposes an automatic approach to generate quadrilateral meshes for the geometric models with complex feature constraints. Firstly, the region is decomposed into sub-regions by the constraints, and then the quadrilateral mesh is generated in each sub-region that satisfies the constraints. A method that deals with constraint lines and points is presented. A distribution function is proposed to represent the distribution of mesh size over the region by using the Laplace equation. The density lines and points can be specified inside the region and reasonable mesh size distribution can be obtained by solving the Laplace equation.

An automatic method to define sub-regions is presented, and the user interaction can be avoided. An algorithm for constructing loops from constraint lines is proposed, which can deal with the randomly distributed constraint lines in a general way. A method is developed to deal with constraint points and quality elements can be generated around constraint points. A function defining the distribution of mesh size is put forward. The examples of constrained quadrilateral mesh generation in actual engineering analysis are presented to show the performance of the approach.

An automatic approach to constrained quadrilateral mesh generation is presented in this paper. It can generate required quality meshes for special applications with complex internal feature constraints.

The purpose of this paper is to investigate the integration of discrete event simulation (DES) and value stream mapping (VSM) to enhance the productivity of road surfacing operations by achieving high production rates and minimum road closure times. Highway infrastructure is one of the most valuable assets owned by the public sector. The success of national and local economies as well as quality of life of the general public depend on the efficient operations of highways. Ensuring smooth traffic operations requires maintenance and improvements of the highest standard.

Research approach involved the use of primary data collected from direct observation, interviews, review of archival records and productivity databases. Based on this, process maps and value stream maps were developed which were subsequently used to produce discrete event simulation models for the exploration of different optimisation scenarios.

This research highlights the synergistic relationship between VSM and DES in driving innovation in construction processes. Identified factors that affect roadworks process productivity include machine, manpower, material, information, environment and method-related factors. A DES model is presented to optimise the process and increase the production rates. A hybrid DES-VSM approach ensures an integrated approach to process optimisation.

This study is an application of hybrid version of previously published DES-VSM framework in the manufacturing sector. The present study has extended and tested its applicability within road surfacing operations. The different what-if scenarios presented in this paper might not be applicable to other parts of the world owing to various constraints. The study has focused on addressing the waste production inherent in pavement laying process. Even though external variables could possibly influence pavement process, those were ignored to allow for in-depth focus on the process under consideration.

Road users are one of the most important stakeholders that will benefit from the positive implications of this study. Private resurfacing companies and transport departments can optimise their overall process and style of working by comparing their end-to-end process and work plans with the ones mentioned in this paper. It will boost the productivity of equipment like planners, pavers and other machines used for resurfacing operations.

Existing approaches to process modelling such as VSM and process diagrams are constrained by their effectiveness in the analysis of dynamic and complex processes. This study presents a DES-based approach to validate targeted improvements of the current state of road surfacing processes and in exploration of different optimisation scenarios.

The purpose of this study is to analyse the problem of high binder content in sand mould and to solve it. Meanwhile, to increase build speed, especially for heavy casting’s sand mould with a high value in layer height, such as 2 mm in construction instead of the industry standard of 0.3 mm, line forming for three-dimensional (3D) sand mould printing is researched.

Brief introduction of 3D sand mould printing and key issues are given first. Then, this paper quantitatively analyses binder content in sand mould. Finally, to acquire sand mould with appropriate binder content and high build speed, line forming combining traditional furan no-bake sand manufacture technique is researched, as well as relevant feasible schemes and current progress.

The study shows that compared with traditional technique, binder content in sand mould produced by available 3D printing technique is too high, bad for sand mould’s properties and quality of castings, while line forming brings guaranteed binder content and improved build speed.

More experiments are needed to demonstrate quantitative analysis of binder content and to obtain flowability of moist sand, detailed structure design of nozzle and practical build speed, as well as methods of circulation of materials considering solidification time.

Line forming with higher build speed and suitable binder content means excellent properties of sand mould and castings as well, bringing obvious implication for moulds industries and manufacturing industry.

This new method could increase build speed and meanwhile guarantee binder content. Thus, its application prospect is promising.

Currently, the existing similar simulation is still limited in the following aspects: un-rotatable laboratory devices, the difficulty in the pavement on steep seams and great error of the experimental data.

To address above-mentioned problems, this study combined theoretical analysis and numerical simulation and developed a rotatable experimental system for similar simulation on steep coal seam mining on the premise of ensuring experimental safety.

The present experimental system mainly consists of the model support, the rotation system and the bearing system. By taking into account the experimental requirements and actual laboratory space, the sizes of the model support and the bearing system were determined. Considering the requirements in space limit and rotation stability, the rotation mode of vertical sliding on the left side and the horizontal sliding on the lower side was designed.

Using programmable logic controller automatic angle control technology, the rotation angle, velocity and displacement of the model can be automatically adjusted and controlled so as to achieve safe rotation and precise control. Finally, the calculation method of the mass of the required similar materials for paving the coal strata at different inclination angles and in different horizons was analyzed, and the related mass proportion calculation software was developed.