Search Results (5)

Cement mortar is made of a combination of cement, sand, and water, mixed in the right proportions. It is ideal for erecting walls and masonry structures, including those that must bear heavy loads. In addition, it is used in places that are exposed to higher humidity and in facilities located below ground level. The potential uses of a mortar are determined by material modification. The aim of the experimental studies was to evaluate the effect of high temperature on the microstructure and mechanical properties of cement mortars modified with polypropylene fiber. The novelty of this study is an attempt to compare the use of different types of polypropylene fibers in mortars heated at different temperatures. Cement mortars based on Portland cement CEM I 42.5 R with a constant content of three types of fibers in the amount of 0.9 kg/m³ were designed^. The samples were cured and then heated in an oven at 300, 500 and 700 °C. The functional properties of cement mortars, i.e., density, flexural and compressive strength after 28 and 56 days of maturation, as well as flexural and compressive strength at elevated temperature, were determined using samples of 40 × 40 × 160 mm. By modifying cement mortars with fibers, it is possible to obtain a cement composite with good strength parameters which is, at the same time, resistant to high temperature. Full article

Currently, China is facing the problems of chaotic governance of end-use agricultural water conservancy facilities and a serious waste of agricultural water. To address the above issues, China launched a pilot policy of reforming the property rights of agricultural water facilities in 2014. In this study, we obtained data from 328 farm households through a microscopic study of the pilot property rights reform in Yunnan Province. We found that the reform has resulted in two typical property rights models: “Multiple cooperative governance” and “Private contract governance”. The impact of the reform on the maintenance quality of irrigation facilities and farmers’ water-saving technology adoption behavior was empirically analyzed using the Oprobit and IV-Oprobit methods. The study found that: (1) the property rights reform significantly improved the quality of maintenance of facilities while promoting farmers’ water-saving technology adoption behavior. (2) Heterogeneity analysis revealed that the degree of non-farming of farmers had a negative moderating effect on the quality of facility maintenance and a positive moderating effect on the adoption of water-saving technologies, and the physical health of farmers had a negative moderating effect on the quality of facility maintenance. (3) There was no significant difference in the quality of facility maintenance between the “Private contract model” and the “Multiple cooperative governance model”, but the former had higher water supply capacity; in addition, farmers under the “Multiple cooperative governance model” mainly used drip irrigation technology, whereas farmers under the “Private contract governance model” mainly used sprinkler irrigation technology. The findings of this study provide Chinese experience in promoting the governance of agricultural water facilities and promoting the water-saving behavior of farmers. Full article

China is implementing a pilot project to reform the property rights of farmland water facilities to solve the serious problems of chaotic end-of-pipe governance and inefficient irrigation from farmers. Based on microscopic research data of farm households in a typical pilot in Lu Liang County, Yunnan Province, in China, this study uses the Tobit model, and SEM was used to explore the impact of property rights reform on the irrigation efficiency of farmers and the potential mechanism paths. We further analyzed the differences in governance logic and irrigation efficiency between the two property rights models of “multiple cooperative governance” and “private contract governance” formed after the reform. The findings are as follows: (1) Compared with nonreformed areas, reformed areas have a higher promotion of adoption of water-saving technologies and a better quality of facility maintenance, which significantly contributes to irrigation efficiency, but farmers’ perception of water scarcity negatively affects irrigation efficiency; (2) there are differences between the “multiple cooperative governance model” and “private contract governance model” in terms of the mechanism paths to improve irrigation efficiency, resulting in different focuses between the two models, in which the former one has better irrigation efficiency while cutting off some of the farmers’ benefits and the latter benefits more farmers while losing some of the irrigation efficiency. Finally, this study recommends that China should continue to promote the reform of farmland water property rights while focusing on promoting water conservation technologies, improving the quality of facility maintenance and facility water supply capacity, enhancing farmers’ awareness of water scarcity, and implementing a more water-efficient “multiple cooperative governance model”. The results of this study provide a model with Chinese characteristics for developing property rights policies and governance models for farmland water facilities in developing countries. Full article

Underground development covers a wide range of underground uses, transportation and infrastructures networks; water and energy storage facilities; municipal spaces, housing, business and manufacturing facilities; and overall exploitation of Urban Underground Space (UUS). According to the Greek legal framework on properties underground, transportation networks, such as the metro, are developed deep enough that no compensation is due to surface parcel owners, which are usually a public entity. The current Greek cadastral system is two-dimensional and there are no records for underground transportation networks. As the need for the exploitation of UUS is arising, especially in densely populated Greek cities, such as Athens, the detailed documentation of transportation networks 3D underground property rights is essential. Herein is presented the technical and legal definition of the 3D underground property rights of the Piraeus Metro Station that is constructed in Piraeus Municipality UUS. Three-dimensional underground models for both Piraeus Station and official cadastral parcels are created so as to identify their 3D spatial intersection. For the identification of their legal and spatial status in 2D, the UUS was subdivided into layers in respect to the station’s vertical infrastructure and then correlated to the current cadastral 2D spatial data. The presented 3D underground property rights of Greece’s major urban underground transportation network facilitates its registration in the current 2D Greek cadastral system and contributes to the better understanding and the identification of legal and technical aspects of UUS rights in Greece. Full article

New light envelopes for buildings need a holistic vision based on the integration of architectural design, building simulation, energy management, and the curtain wall industry. Water flow glazing (WFG)-unitized facades work as transparent and translucent facades with new features, such as heat absorption and renewable energy production. The main objective of this paper was to assess the performance of a new WFG-unitized facade as a high-performance envelope with dynamic thermal properties. Outdoor temperature, variable mass flow rate, and solar radiation were considered as transient boundary conditions at the simulation stage. The thermal performance of different WFGs was carried out using simulation tools and real data. The test facility included temperature sensors and pyranometers to validate simulation results. The dynamic thermal transmittance ranged from 1 W/m²K when the mass flow rate is stopped to 0.06 W/m²K when the mass flow rate is above 2 L/min m². Selecting the right glazing in each orientation had an impact on energy savings, renewable energy production, and CO₂ emissions. Energy savings ranged from 5.43 to 6.46 KWh/m² day in non-renewable energy consumption, whereas the renewable primary energy production ranged from 3 to 3.42 KWh/m² day. The CO₂ emissions were reduced at a rate of 1 Kg/m² day. The disadvantages of WFG are the high up-front cost and more demanding assembly process. Full article