Search results for "technical"
showing 10 items of 955 documents
Assessing a Local Losses Evaluation Procedure for Low-Pressure Lay-Flat Drip Laterals
2014
In the past, several research experiments have focused on the hydraulic characterization of traditional drip irrigation systems, and different design methodologies have been proposed with the aim of achieving very high emitter discharge uniformity (EU). The increasing use of low-pressure lay-flat drip laterals, characterized by a thin-walled polyethylene pipe, makes necessary a specific determination of their hydraulic properties, aimed to a correct design of such systems. Here, the validity of an empirical local losses estimation model was assessed for five different commercial lay-flat drip tapes. Moreover, the errors in the maximum lateral lengths obtained for a fixed emitter uniformity,…
New Solution of Classical Hydraulic Jump
2009
This technical note, applying dimensional analysis and incomplete self-similarity, proposes a new functional relationship for the sequent depth ratio for hydraulic jumps over both smooth and rough horizontal beds. For the smooth bed condition, experimental measurements in the literature were used to calibrate the new relationship. For the rough bed condition the data of a previous investigation were used with new measurements carried out in a rectangular horizontal flume having a gravel bed. Finally, a generalized solution of the sequent depth ratio is proposed.
Generalization of Shear Truss Model to the Case of SFRC Beams with Stirrups
2012
A theoretical model for shear strength evaluation of fibrous concrete beams reinforced with stirrups is proposed. The formulation is founded on the theory of plasticity and the stress field concepts, generalizing a known plastic model for calculating the bearing capacity of reinforced concrete beams, to the case of fibrous concrete. The beneficial effect of steel fibres is estimated taking into account the residual tensile strength of fibrous concrete, by modifying an analytical constitutive law which presents a plastic plateau as a post-peak branch. Around fifty results of experimental tests carried out on steel fibrous concrete beams available in the literature were collected, and a compa…
Soil management effect on soil penetration resistance in the vineyard
2013
In environments characterized by steep slopes or arranged in terraces, among the shallow tillage systems, rototilling is extensively used. However, the effect of the repeated use of rototilling has a considerable influence on soil characteristics; it appears finely powdered, soft and without structure. In order to limit these inconveniences, an innovative self-propelled machine equipped with working tools as a spade, to be used in steep slopes or arranged in terraces areas, was designed by the Mechanics Section of the SAF (Scienze Agrarie e Forestali) Department of the University of Palermo in cooperation with Agrotec company, Padua, Italy. The aim of this study is to compare the effects of…
Composite Material Recycling Technology—State-of-the-Art and Sustainable Development for the 2020s
2021
Recently, significant events took place that added immensely to the sociotechnical pressure for developing sustainable composite recycling solutions, namely (1) a ban on composite landfilling in Germany in 2009, (2) the first major wave of composite wind turbines reaching their End-of-Life (EoL) and being decommissioned in 2019–2020, (3) the acceleration of aircraft decommissioning due to the COVID-19 pandemic, and (4) the increase of composites in mass production cars, thanks to the development of high volume technologies based on thermoplastic composites. Such sociotechnical pressure will only grow in the upcoming decade of 2020s as other countries are to follow Germany by limiting and ba…
Hydraulic jumps on rough beds
2007
This paper presents the results of an experimental investigation on the hydraulic jump on horizontal rough beds. Experiments were carried out to study the effect of bed roughness on both the sequent depth ratio and the roller length. The investigation allowed the writers to positively test the reliability of a new solution of the momentum equation for the sequent depth ratio as a function of the Froude number and the ratio between the roughness height and the upstream supercritical flow depth. The applicability of some empirical relationships for estimating the roller length was also tested.
Comparative Analysis of Four New Alternative Types of Roundabouts: “Turbo”, “Flower”, “Target” and “Four-Flyover” Roundabou
2016
Analysis of literature shows that “modern roundabouts” nowadays exist in all European countries, as well as in more than 60 countries elsewhere in the world. Nowadays, a growing number of studies, presented in scientific and professional literature, point out a poor traffic safety characteristics of “standard” two-lane roundabouts and lower capacity then was expected. These problems are resolved in more ways in different countries; however the solution, whereby the number of conflict spots is diminished has proven to be the most successful. Lower number of conflict spots is one of characteristics of the alternative types of roundabouts. The alternative types of roundabouts are usually more …
A Topic-Case Driven Methodology for Web Course Design
2008
A topic-case driven methodology for a web course design and realization process is based on software engineering metaphors for capturing the necessary steps in creating web courses by means of a content-based development method. The methodology combines instructional issues to design phases that guide teachers and instructors to design and implement online courses. The methodology has been used by students of computer science, teacher education as well as professional university educators from different educational fields. The results from these experiences have been reported as case studies. In this chapter, the methodology is introduced with the summarized results from three case studies.
Recommendation of RILEM TC237-SIB: protocol for characterization of recycled asphalt (RA) materials for pavement applications
2018
This recommendation proposes an experimental protocol to characterize Recycled Asphalt (RA) materials. The guidelines presented in this document are based on the results of a Round Robin Test (RRT) organized by the RILEM Technical Committee 237-SIB “Testing and characterization of sustainable innovative bituminous materials and systems” and provide information on the testing procedure, data analysis and indications for the preparation of a test report.
GREENHOUSE EFFECT REDUCTION THROUGH MINE METHANE VALORIZATION: OVERVIEW AND FEASIBILITY STUDY
2017
Although the main reason for the extraction of methane from coal beds continues to address ensuring the safety of workers, an important driver is the need to reduce emissions of greenhouse gases. In order to identify potential technical problems specific for available technologies implementation, we performed a comparative critical analysis, based on which the technically feasible systems resulted, their further selection being based on detailed analysis in financial and investment terms. The research goal was to establish options for using methane gas discharged through central degassing and main ventilation stations currently operational mines in the Jiu Valley collieries; through its lev…