Vertical green walls for noise and temperature reduction – an experimental investigation
26 Apr 2021-Science and Technology for the Built Environment (Taylor & Francis)-Vol. 27, Iss: 6, pp 806-818
TL;DR: The abundance of heat-trapping asphalt and concrete, smog, and heat emitted from buildings and vehicles is one of the major reasons for the prevailing high temperature, air and noise pollution in c
Abstract: The abundance of heat-trapping asphalt and concrete, smog, and heat emitted from buildings and vehicles is one of the major reasons for the prevailing high temperature, air and noise pollution in c
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TL;DR: In this article, a long-term field soil survey has been conducted to monitor and understand the temporal variations of sound speed due to the changes of soil physical properties under natural conditions, and the effects of water potential, moisture content, soil temperature, and depth on sound speed were assessed.
Abstract: In order to monitor and understand the temporal variations of sound speed due to the changes of soil physical properties under natural conditions, a long‐term field soil survey has been conducted. Measurements of sound speed, soil temperature, soil moisture content, and water potential were performed continuously, along with the measurements of surface temperature and precipitation over a period of 2 years. The effects of water potential, moisture content, soil temperature, and depth on sound speed were assessed. Analysis of the data shows that there is a power law relationship between the sound speed and water potential. It is also found that the water potential is the dominant influence on the sound speed, whereas the moisture content and temperature have relatively minor impacts. Brutsaert and Luthin’s theory was employed to calculate the sound speed as a function of the effective stress. The theoretical predictions were compared with the experimental data and they are in good agreement. The study sugg...
26 citations
TL;DR: In this paper , a review of green construction with focus on history, carbon emissions, policies, models, life cycle assessment, and sustainable materials such as biochar, bioplastic, agricultural waste, animal wool, fly ash and self-healing concrete is presented.
Abstract: Abstract The construction industry is a major user of non-renewable energy and contributor to emission of greenhouse gases, thus requiring to achieve net-zero carbon emissions by 2050. Indeed, construction activities account for 36% of global energy consumption and 39% of global carbon dioxide emissions. Reducing carbon emissions requires adapted government policies, carbon emission analysis and calculation models, and sustainable materials. Here, we review green construction with focus on history, carbon emissions, policies, models, life cycle assessment, and sustainable materials such as biochar, bioplastic, agricultural waste, animal wool, fly ash and self-healing concrete. Analysis of carbon emissions over the building life cycle shows that the construction phase accounts for 20–50% of total carbon emissions. The average ratio of construction phase annual emissions to operation phase emissions is 0.62. We present national policy frameworks and technology roadmaps from the United States of America, Japan, China, and the European Union, highlighting plans to achieve carbon neutrality in the building sector.
7 citations
TL;DR: Wang et al. as mentioned in this paper developed an evaluation index system of green building design schemes and an evaluation method based on the projection pursuit model to overcome the shortage of a systematic evaluation index and comprehensive evaluation method.
Abstract: The popularization and use of green buildings are of great significance for reducing the carbon emissions of buildings and achieving sustainable development. Scientific evaluation of the green building design scheme is the key factor in ensuring the popularization and use of green buildings. To overcome the shortage of a systematic evaluation index system and comprehensive evaluation method, an evaluation index system of green building design schemes and an evaluation method based on the projection pursuit model were developed. First, according to the needs of green building development, an evaluation index system of green building design schemes was systematically constructed from the five aspects of the economy, the resource utilization index, environmental impacts, technical management, and social impacts. The calculation methods of all secondary indexes are provided in detail. Then, a novel evaluation method based on the projection pursuit model optimized by the atomic orbital search was constructed. This method searches for key influencing factors and determines the evaluation grade from the evaluation data structure, and realizes the scientific and objective evaluations of green building design schemes. Finally, the Nanchang Hengda Project was selected to conduct a detailed empirical study. The research results show that the incremental net present value of the investment, the energy consumption of the air conditioning system, and the ratio of the window area to the indoor area are the most important secondary indexes. Moreover, the environmental impact index was found to be the most important primary index. Via comparisons with different optimization algorithms and evaluation methods, the superiority of the proposed model is proven.
1 citations
TL;DR: In this article , the authors present the historical context of resonant metamaterials, the current progress of periodic 2D and 3D structures, and the possible future outcomes from the seismic METAMaterials (SMs), and it relates them with their elastic counterparts to the natural METAMOLA (NMs).
Abstract: The modern construction revolution throughout the past two decades has brought the need for ground vibration mitigation, and this has been one of the major study areas. These studies were mainly focused on the effect of forestation on vibration reduction as the available natural metamaterial. Physical methods such as the finite element method and the boundary conditions of 2D and 3D applications in ground vibration reduction have been developed. Many researchers, scientists, and organizations in this field have emphasized the importance of these methods theoretically and numerically. This paper presents the historical context of resonant metamaterials (MMs), the current progress of periodic 2D and 3D structures, and the possible future outcomes from the seismic metamaterials (SMs), and it relates them with their elastic counterparts to the natural metamaterial (NMs). The idea of bandgaps (FBGs) in the frequency range of interest is reviewed and discussed in some detail. Moreover, the attenuation associated with ground vibrations, noise, seismology, and the like is explained by managing the peculiar mechanisms of ground vibrations. However, a comprehensive computational review focuses on shielding MMs for ground vibration mitigation in urban areas. This phenomenon led to unique features for various techniques to control the bandgap width for various construction applications. Ecological solutions involve the creation of an economic, environmentally based seismic shield for both the Bragg scattering and the local resonance bandgaps. Reportedly, additive studies based on numerical simulation and experiments have improved the functionality of the 2D and 3D periodic structures. It was found that the mechanical properties differ (i.e., stiffness, Poisson’s ratio, and bulk density) and that the geometrical parameters (i.e., lattice, model dimensions, distance from vibration sources, and number of periodic structures) exhibited strong effects on the width and location of the derived FBGs. The geometrical properties of the used unit cell have a strong effect on the attenuation mechanism. Although deep analysis was created in much of the previous research, it was revealed, based on that research, that the attenuation mechanism is still unclear. However, this review article presents a detailed exposition of the recent research progress of the seismic metamaterials, including 2D, 3D, and the main mechanisms of the theoretical backgrounds of energy attenuation. It also summarizes the effects of the factors on the width and location of the bandgaps at a low frequency. In addition, the natural metamaterials and the study of the urban environment are surveyed. The major findings of this review involve the effectiveness of NMs for different functionalities in ground vibration attenuation, which leads to diverse purposes and applications and proposes a roadmap for developing natural materials for clean and quiet environments.
1 citations
TL;DR: In this paper , the authors used Helicrysum italicum in the green healing wall to improve the urban environment with benefits for the population wellbeing and a potential to obtain value-added bioactive extracts.
1 citations
References
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TL;DR: In this article, a transgenic plant expressing an isopentenyltransferase gene driven by a stress-and maturation-induced promoter was used to suppress the senescence of leaves during a long drought period.
Abstract: Drought, the most prominent threat to agricultural production worldwide, accelerates leaf senescence, leading to a decrease in canopy size, loss in photosynthesis and reduced yields. On the basis of the assumption that senescence is a type of cell death program that could be inappropriately activated during drought, we hypothesized that it may be possible to enhance drought tolerance by delaying drought-induced leaf senescence. We generated transgenic plants expressing an isopentenyltransferase gene driven by a stress- and maturation-induced promoter. Remarkably, the suppression of drought-induced leaf senescence resulted in outstanding drought tolerance as shown by, among other responses, vigorous growth after a long drought period that killed the control plants. The transgenic plants maintained high water contents and retained photosynthetic activity (albeit at a reduced level) during the drought. Moreover, the transgenic plants displayed minimal yield loss when watered with only 30% of the amount of water used under control conditions. The production of drought-tolerant crops able to grow under restricted water regimes without diminution of yield would minimize drought-related losses and ensure food production in water-limited lands.
796 citations
TL;DR: In conclusion, experiments to genetically engineer expression of fish antifreeze proteins have not improved freezing tolerance of sensitive species, and a better strategy may be to confer tolerance of cellular dehydration.
491 citations
"Vertical green walls for noise and ..." refers background in this paper
...The noise source was a combination of transportation vehicle engine, human conversation and work noise that simulated urban noise pollution sources (Renterghem and Botteldooren 2010, Barclay, Kang, and Sharples 2012)....
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TL;DR: In this paper, a study of 8 different vertical greenery systems (VGSs) installed in HortPark to evaluate the thermal impacts on the performance of buildings and their immediate environment based on the surface and ambient temperatures.
487 citations
TL;DR: Canopy-scale evaporation rate (E) and derived surface and aerodynamic conductances for the transfer of water vapour (gs and ga, respectively) are reviewed for coniferous forests and grasslands andBoundary-line relationships between gs and light and air saturation deficit (D) vary considerably.
Abstract: Canopy-scale evaporation rate (E) and derived surface and aerodynamic conductances for the transfer of water vapour (gs and ga, respectively) are reviewed for coniferous forests and grasslands. Despite the extremes of canopy structure, the two vegetation types have similar maximum hourly evaporation rates (Emax) and maximum surface conductances (gsmax) (medians = 0.46 mm h-1 and 22 mm s-1). However, on a daily basis, median Emax of coniferous forest (4.0 mm d-1) is significantly lower than that of grassland (4.6 mm d-1). Additionally, a representative value of ga for coniferous forest (200 mm s-1) is an order of magnitude more than the corresponding value for grassland (25 mm s-1). The proportional sensitivity of E, calculated by the Penman-Monteith equation, to changes in gs is >0.7 for coniferous forest, but as low as 0.3 for grassland. The proportional sensitivity of E to changes in ga is generally ±0.15 or less.
378 citations
"Vertical green walls for noise and ..." refers background in this paper
...Kelliher, Leuning, and Schulze (1993) studied the relationship between plant canopy evaporation and soil water content and proved that the evaporation of Psuedotsuga menziesii, Pinus Sylvestris, Agropyron and Lolium perene species enhance from 0.5 to 8 with a relative increase in soil water content…...
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...The combined evaporation and transpiration process helps in enhancing the cooling effect of PGW (Kelliher, Leuning, and Schulze 1993)....
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TL;DR: The results quantify the effects of woody plants on the microclimate with respect to soil temperature and evaporation, which in turn affect herbaceous and Woody plants by modifying factors such as germination, the potential for facilitation, and the amount of plant‐available water.
Abstract: The canopies of woody plants in semiarid ecosystems modify the microclimate beneath and around them, with canopy patches usually having lower soil temperatures than intercanopy patches. However, lacking are studies that have evaluated how heterogeneity in soil temperature, induced by woody plant canopies, influences soil evaporation rates and the consequent effects on plant‐available water. Soil temperatures were measured and soil evaporation rates were estimated for canopy and intercanopy patches in a semiarid pinon‐juniper woodland (Pinus edulis and Juniperus monosperma) in northern New Mexico. Soil temperature was measured at 2‐cm depths in four canopy and four intercanopy locations during 1994. Maximum soil temperature in intercanopy patches was greater than in canopy patches between May and September, by as much as 10°C, while soil temperatures in intercanopy patches were lower than in canopy patches during colder parts of the day in the fall and winter months. Equations for soil drying rates for san...
362 citations