scholarly journals Influence of the Hydrogel Amendment on the Water Retention Capacity of Extensive Green Roof Models

2020 ◽  
Vol 21 (1) ◽  
pp. 195-204
Author(s):  
Iwona Deska ◽  
Maciej Mrowiec ◽  
Ewa Ociepa ◽  
Agnieszka Lewandowska
Keyword(s):  
Water Retention ◽  
Green Roof ◽  
Water Retention Capacity ◽  
Retention Capacity ◽  
Extensive Green Roof

Innovative green roof with high water retention and durability

2019 ◽  
Author(s):  
Thomas Cornelius Buch-Hanser ◽  
Guangli Du ◽  
David John Duffus
Keyword(s):  
Water Retention ◽  
Green Roof ◽  
Water Reservoir ◽  
Green Roofs ◽  
High Water ◽  
Water Retention Capacity ◽  
Storm Events ◽  
Concrete Element ◽  
Retention Capacity ◽  
Roof System

<p>Given the rapid increase in urban populations, combined with the effects of climate change, cities are struggling to provide green spaces to address liveability as well as adaptability to new challenges. Water retention and bio-diversity are the main advantages of green roofs. There are, however, limitations to green roofs that impede their acceptance and proliferation. There is for example uncertainty on how much water they retain during major storm events. In terms of building technology, green roofs today aren’t robust, and the risk for leakage through the roof membrane is disproportionally high when compared to the cost. A newly developed innovative green roof system with high water retention capacity and high durability will be presented. The patented prefabricated technology incorporate insulation and membrane into a single concrete element, ensuring improved robustness, quickened building times and a long term durable product. Initial indications for pricing indicate that the system is price-neutral when compared with green roofs as they are built today. The optimized structural performance obtain same loadbearing capacity, as existing systems, in spite of the relatively increased space created for water reservoir, without compromising the insulation capacity, hence the new green roof system further contribute to increased sustainability.</p>

scholarly journals Impact of the Hydrogel Amendment and the Dry Period Duration on the Green Roof Retention Capacity

2020 ◽  
Vol 27 (3) ◽  
pp. 357-371
Author(s):  
Iwona Deska ◽  
Maciej Mrowiec ◽  
Ewa Ociepa ◽  
Michał Michniewski
Keyword(s):  
Urban Areas ◽  
Water Retention ◽  
Drainage Basin ◽  
Green Roof ◽  
Green Roofs ◽  
Water Retention Capacity ◽  
Retention Capacity ◽  
Rainwater Infiltration ◽  
Basin Surface ◽  
Significant Difference

AbstractClimate changes as well as the urbanisation and economic development influence the characteristics of the stormwater runoff in the cities. The sealing of drainage basin surface leads to an increase of the runoff intensity, thereby decreasing the rainwater infiltration. This situation can lead to the risk of flooding in urban areas. Therefore, especially in great cities there is a need for application of such solutions that will support the operation of the sewage systems. The examples of such solutions are, among others, the green roofs. The paper presents the results of investigation of the water retention capacity of 4 green roof models containing following growing media: (1) the typical green roof substrate without any amendments, (2) the substrate with addition of about 1 % by weight of hydrogel (the cross-linked potassium polyacrylate), (3) the substrate containing about 0.25 % by weight of hydrogel, (4) the substrate with addition of expanded clay and perlite. The models were not vegetated in order to investigate only the water retention capacity of drainage elements and substrates. The water retention capacity of green roof models was investigated in the laboratory conditions with use of artificial precipitations simulated after diverse antecedent dry weather periods (ADWP) amounting to: 1, 2, 5, 7, and 12 days. The intensities of artificial precipitations were relatively high and ranged from 1.14 to 1.27 mm/min, whereas their durations ranged from 7.75 to 12.56 min. These values of intensities and durations corresponded to the design rainfall intensities calculated using Blaszczyk’s equation for annual rain depth equal to 600 mm and the return periods ranged from 5 to 15 years. The obtained results indicate that the water retention capacity of green roof models, expressed as the volumes (or depths) of rainwater retained within their structures, increases with an increase of ADWP. Results indicate that the relation between ADWP and the amount of water retained in the layers of green roofs in the case of relatively short antecedent dry weather periods provided for the analysis (from 1 to 7 days) may be approximately linear. The results of the one-way ANOVA indicate that in the case of all models there is a statistically significant difference between the values of retention depth for specified ADWP (p < 0.001). During more than half of simulated precipitations, especially in the case of longer ADWPs lasting 5, 7, and 12 days the best water retention capacity had Model 3, with substrate containing about 0.25 % by weight of hydrogel. On the other hand, the results show that the weakest retention capacity had Model 2 (with substrate containing 1 % by weight of hydrogel). In the case of longer ADWPs (lasting 7 and 12 days) relatively weak water retention capacity had Model 4 (with substrate containing the addition of expanded clay and perlite). It can be concluded that too large amount of hydrogel added to the substrate can have an unfavourable impact on the water retention capacity of green roofs.

scholarly journals Drainage flux simulation of green roofs under wet conditions

2018 ◽  
Vol 49 (4) ◽  
pp. 242-252 ◽  
Author(s):  
Francesco Bettella ◽  
Vincenzo D'Agostino ◽  
Lucia Bortolini
Keyword(s):  
Water Retention ◽  
Green Roof ◽  
Green Roofs ◽  
Water Retention Capacity ◽  
Growth Media ◽  
Initial Water Content ◽  
Retention Capacity ◽  
Worst Case ◽  
Steady State Condition ◽  
Growing Medium

The role of green roofs in reducing drainage fluxes is known, but despite extensive analysis in the literature, methods to predict the hydrologic performance for a given green roof composition are scarce. These methods are useful for the hydraulic design and for planning regulations that impose specific hydrological responses. This research investigates on the prediction of the drainage fluxes produced below a green roof with initial water content equal to its water retention capacity (worst-case scenario). Laboratory tests were performed to analyse the rainfall-drainage relationship for green-roof and single components (growing media and drainage storage layers) under specific rainfall intensities. Two types of largely used drainage/storage layers and growth media were analysed, both singularly and in combination. The experiments consider two rainfall events lasting 10 min with constant intensity. The results indicate that the Curve Number (CN) method (U.S. Soil Conservation Service) with a simple adaptation can be used to reproduce the green-roof hydrologic behaviour under antecedent moisture conditions comparable with those of the experiments. In fact, the water retention capacity, controlling the water-output initiation below the green roof, can be used as threshold variable of a step function, above which the CN method is applicable and below which drainage fluxes are practically null. Through this position, the CN assignment for a composite greenroof can be consistently estimated using the proprieties of the single components (drainage/storage layer and growing medium) and it provides values that are very close to those of waterproof media and quite higher than those suggested in companion researches. Drainage amounts are predicted with a standard error equal to 1.50 mm, which corresponds to 5.7% of the mean value observed. After rain initiation, the steady state condition of the drainage flux has proved to be markedly affected by the growing medium and drainage layer composing the system, which result effective in discriminating the green roof performance.

scholarly journals Hydrologic Performance of an Extensive Green Roof under Intensive Rain Events: Results from a Rain-Chamber Simulation

2021 ◽  
Vol 13 (6) ◽  
pp. 3078
Author(s):  
Elena Giacomello ◽  
Jacopo Gaspari
Keyword(s):  
Water Retention ◽  
Green Roof ◽  
Green Roofs ◽  
International Standards ◽  
Dimensionless Number ◽  
Runoff Coefficient ◽  
Retention Performance ◽  
Extensive Green Roof ◽  
Rain Events ◽  
Hydrologic Performance

The water storage capacity of a green roof generates several benefits for the building conterminous environment. The hydrologic performance is conventionally expressed by the runoff coefficient, according to international standards and guidelines. The runoff coefficient is a dimensionless number and defines the water retention performance over a long period. At the scale of single rain events, characterized by varying intensity and duration, the reaction of the green roof is scarcely investigated. The purpose of this study is to highlight how an extensive green roof—having a supposed minimum water performance, compared to an intensive one—responds to real and repetitive rain events, simulated in a rain chamber with controlled rain and runoff data. The experiment provides, through cumulative curve graphs, the behavior of the green roof sample during four rainy days. The simulated rain events are based on a statistical study (summarized in the paper) of 25 years of rain data for a specific location in North Italy characterized by an average rain/year of 1100 mm. The results prove the active response of the substrate, although thin and mineral, and quick draining, in terms of water retention and detention during intense rain events. The study raises questions about how to better express the water performance of green roofs.

scholarly journals Chemical Composition and Functional Properties of Dietary Fibre Concentrates from Winemaking By-Products: Skins, Stems and Lees

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1510
Author(s):  
María Ángeles Rivas ◽  
Rocío Casquete ◽  
María de Guía Córdoba ◽  
Santiago Ruíz-Moyano ◽  
María José Benito ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Functional Properties ◽  
Dietary Fibre ◽  
Water Retention ◽  
Point Of View ◽  
Water Retention Capacity ◽  
Retention Capacity ◽  
Oil Retention ◽  
High Antioxidant Activity ◽  
By Products

The objective of this study was to evaluate, from a technological and nutritional point of view, the chemical composition and functional properties of the industrial winemaking by-products, namely skins, stems and lees. The chemical and physical characteristics, as well as the functional properties (fat and water retention and swelling capacity, antioxidant capacity, and their prebiotic effect), of the dietary fibre of these by-products were studied. The results showed that the skins, stems, and lees are rich in fibre, with the stem fibre containing the highest amounts of non-extractable polyphenols attached to polysaccharides with high antioxidant activity and prebiotic effect. Lee fibre had the highest water retention capacity and oil retention capacity. The results reveal that winemaking by-products could be used as a source of dietary fibre with functional characteristics for food applications.

Host preferences of low-trunk vascular epiphytes in a cloud forest of Veracruz, Mexico

2005 ◽  
Vol 21 (6) ◽  
pp. 651-660 ◽  
Author(s):  
Klaus Mehltreter ◽  
Alejandro Flores-Palacios ◽  
José G. García-Franco
Keyword(s):  
Water Retention ◽  
Cloud Forest ◽  
Water Retention Capacity ◽  
Retention Capacity ◽  
Host Preferences ◽  
Host Group ◽  
Vascular Epiphytes ◽  
Lower Trunk ◽  
Tree Ferns ◽  
Epiphyte Species

The diversity, abundance and frequency of vascular epiphytes on the lower trunk were compared between two host groups of a Mexican cloud forest: angiosperm trees (n = 72) and tree ferns (n = 28). The bark of the five most frequent host trees and the root mantle of the two tree ferns were analysed for their thickness, water content, water retention capacity and pH. A total of 55 epiphyte species and 910 individuals were found on the 27 host species. On hosts with a dbh range of 5–10 cm, epiphytes were significantly more diverse (4.3±0.9 species per host) and more abundant (12.5±2.2 individuals per host) on tree ferns than on angiosperm trees (1.9±0.2 species per host and 3.9±0.6 individuals per host). However, these differences were not significant for the dbh class of 10–20 cm, because epiphyte numbers increased on angiosperm trees with larger host size, but not in tree ferns. Most epiphyte species had no preference for any host group, but four species were significantly more frequent on tree ferns and two species on angiosperm trees. The higher epiphyte diversity and abundance on tree fern trunks of the smallest dbh class is attributed to their presumably greater age and to two stem characteristics, which differed significantly between host groups, the thicker root mantle and higher water retention capacity of tree ferns. These bark characteristics may favour germination and establishment of epiphytes.

Effect of boiling on nutritional, antioxidant and physicochemical properties of edible plants (Malva parviflora and Myrtillocactus geometrizans)

2021 ◽  
pp. 510
Author(s):  
Sandoval-Gallegos Eli Mireya ◽  
Arias-Rico José ◽  
Cruz-Cansino Nelly del Socorro ◽  
Ramírez-Ojeda Deyanira ◽  
Zafra-Rojas Quinatzin Yadira ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Physicochemical Properties ◽  
Antioxidant Capacity ◽  
Water Retention ◽  
Nutritional Composition ◽  
Total Phenolic ◽  
Water Retention Capacity ◽  
Total Phenolic Compounds ◽  
Retention Capacity ◽  
Malva Parviflora

The aim of the present research was to determine the effect of boiling on nutritional composition, total phenolic compounds, antioxidant capacity, physicochemical and morphological characteristics of two edible plants Malva parviflora (mallow leaf) and Myrtillocactus geometrizans (garambullo flower). The plants had an important nutritional composition as carbohydrates (48-70 %), dietary fiber (36-42 %) and protein (13 %), as well as total phenolic compounds (468-750 mg GAE/100 g db) with a high antioxidant capacity. However, boiling originated the decrease of soluble compounds, carbohydrates, total phenolic compounds, antioxidant capacity and physicochemical properties. Plants changed to dark colors and physicochemical properties were affected, except to water retention capacity, oil retention capacity and viscosity, which had the same values in mallow leaves (raw and boiled), but increased water retention capacity in garambullo flowers, it may be by changes in the morphology observed. Therefore, is to suggest the raw consumption or with minimal cooking of these plants to avoid changes caused by thermal treatment.

Effect of Storage Time on the Physicochemical and Sensory Properties of Man-tou (Chinese Steamed Bread)

2007 ◽  
Vol 3 (3) ◽  
Author(s):  
Kun Sha ◽  
Ping Qian ◽  
Li-Jun Wang ◽  
Zhan-hui Lu ◽  
Li-Te Li
Keyword(s):  
Water Retention ◽  
Storage Time ◽  
Soluble Starch ◽  
Prolonged Storage ◽  
Water Retention Capacity ◽  
Study Quality ◽  
Total Water ◽  
Retention Capacity ◽  
Steamed Bread

In this study, quality of Man-tou, the Chinese traditional steamed bread during storage was studied. Values for water retention capacity, total water solubles, soluble starch, and soluble amylose and amylopectin of Man-tou decreased with storage time. Results showed that hardness, chewiness and gumminess of Man-tou increased, while, springiness cohesiveness and resilience decreased along with prolonged storage time (p<0.05). Sensory evaluation results showed that all sensory rating of Man-tou, including softness, stickiness, cohesiveness, elasticity, taste and total score, dropped drastically within 24 h of storage time (p<0.05). Differential Scanning Calorimeter (DSC) was used to determine crystalline structure of amylopectin in Man-tou, and the value for enthalpy of crystallization was found increased with storage time. Amylopectin crystallization was significantly associated to Man-tou firming (p<0.01).

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