Search results for "Structural Engineering"
showing 10 items of 1998 documents
Chemical oxidation and reduction of hexachlorocyclohexanes: A review
2019
Abstract Lindane (γ-hexachlorocyclohexane) and its isomers (HCH) are some of the most common and most easily detected organochlorine pesticides in the environment. The widespread distribution of lindane is due to its use as an insecticide, accompanied by its persistence and bioaccumulation, whereas HCH were disposed of as waste in unmanaged landfills. Unfortunately, certain HCH (especially the most reactive ones: γ- and α-HCH) are harmful to the central nervous system and to reproductive and endocrine systems, therefore development of suitable remediation methods is needed to remove them from contaminated soil and water. This paper provides a short history of the use of lindane and a descri…
THE INFLUENCE OF TOOL STIFFNESS OF THE LIFETIME OF THE INSERTS IN INTERRUPTED CUTTING OPERATIONS
1989
ABSTRACT In the present paper the influence exerted by the stiffness of the tool-workpiece system under working conditions on tool life up to the fracture of carbide inserts in interrupted cutting is investigated. It is shown how, with the increase in compliance of the system, there is a corresponding increase in the average tool life of the insert which is greater the lesser the cutting speed. The results of tests carried out indicate as a possible cause the amount of damage evident in the successive phase of tool engagement with the workpiece. It was observed how, in this phase, the tool, vibrating at the same rate as the toolholder produces alternations in the cutting force. This effect …
Experimental Study of Vibrations in Face Milling Cutting
2014
The paper consists of a research in designing and experimental analysis using a face milling cutter with round inserts. A general model for the new cutter is proposed taking into consideration multiple aspects regarding monitoring and controling the milling process. A comparison of measured vibrations when cutting with different parameters for two constructions of the milling head is presented. The objective of this vibration comparison is to verify wether the new design behaves in similar way with the classic and proven concept of insert clamping using a central screw.
Influence of Implant Connection, Abutment Design and Screw Insertion Torque on Implant-Abutment Misfit
2020
Background: An accurate fit at the implant-abutment interface is an important factor to avoid biological and mechanical complications. The aim of this study was to evaluate the marginal misfit at the implant-abutment interface on external and Morse taper connection, with straight and angulated abutments under different insertion torque loads. Materials and Methods: A total of 120 implants were used, 60 with external connection (EC) and 60 with Morse taper connection (IC). Straight (SA) (n = 60) and angulated abutments (AA) (n = 60) were randomly screwed to each connection at different torque levels (n = 10 each): 10, 20 and 30 Ncm. All specimens were subjected to thermal and cyclic loading …
Uncertainty Assessment of a Water-Quality Model for Ephemeral Rivers Using GLUE Analysis
2011
Every model is, by definition, a simplification of the system under investigation. Although it would be desirable to reduce the gap between the simulated and the observed behaviors of the system to zero, this reduction is generally impossible owing to the unavoidable uncertainties inherent in any modeling procedure. Uncertainty analyses can provide useful insights into the best model approach to be used for obtaining results with a high level of significance and reliability. The evaluation of parameter uncertainties is necessary for calibration and for estimating the impact of these uncertainties on model performance. In this context, the uncertainty of a river water-quality model developed…
Machine learning techniques to estimate the degree of binder activity of reclaimed asphalt pavement
2022
Part of this research was funded by the project RTI2018-096224-J-I00 that has been cofounded by the Spanish Ministry of Science and Innovation, inside the National Program for Fostering Excellence in Scientific and Technical Research, National Subprogram of Knowledge Generation, 2018 call, in the framework of the Spanish National Plan for Scientific and Technical Research and Innovation 2017-2020, and by the European Union, through the European Regional Development Fund, with the main objective of Promoting technological development, innovation and quality research. Part of this work was financially supported by the Italian Ministry of University and Research with the research Grant PRIN 20…
Systems engineering activities supporting the heating & current drive and fuelling lines systems integration in the European DEMO breeding blanket
2019
This paper describes the contribution given by the application of the systems engineering approach to the European DEMO Breeding Blanket (BB) integration studies, focussing on the integration of Heating & Current Drive (H&CD) and Fuelling Lines (FL) systems. In particular, attention has been paid to the BB-H&CD and BB-FL interfaces identification, definition and capture of the proper interface requirements necessary to drive the integration process and, as a consequence, supply a feedback for the reciprocal design of the interconnected systems. The defined interfaces are synthetically described in the paper and the results of the interface requirements capture process are shown,…
Pricing and infrastructure fees in shaping cooperation in a model of high-speed rail and airline competition
2020
Abstract This paper studies the effects of cooperation in a hub-and-spoke network with high-speed rail and airline competition. The distinctive elements of our analysis are the consideration of: (i) per-passenger airport and rail infrastructure fees; (ii) mixed bundling pricing by partners, and (iii) an airline duopoly in the international market. We show that partners fix the cheapest bundle price of the combined trip, that non-allied operators respond by decreasing the prices per link, and that connecting traffic increases. Per-passenger fees significantly affect the price differences following cooperation. An empirical application confirms that it is privately profitable and that welfare…
Out-of-Plane Behavior of URM Infill: Accuracy of Available Capacity Models
2022
The aim of this paper is to check the accuracy of analytical capacity models available for the prediction of out-of-plane strength of unreinforced masonry (URM) infill walls. The accuracy of the available models is checked by detailed comparison with the existing experimental results. In doing so, both types of capacity models are evaluated: Type I for the prediction of the strength in the undamaged state, and Type II for the prediction of strength reduction in the in-plane damaged state. Results from the calculations are discussed, and the best among the available models are recommended. Furthermore, the influence of orthotropy of the infill masonry in the out-of-plane capacity predicted b…
Hydraulic Design of the Center-Pivot Irrigation System for Gradually Decreasing Sprinkler Spacing
2021
Design strategies that enhance modern irrigation practices, reduce energy consumption, and improve water use efficiency and crop yields are fundamental for sustainability. Although microirrigation is currently a widely applied method, center-pivot irrigation systems have become very popular on large farms, thanks to their automation, wide-coverage, and reliability. Different design procedures have been proposed, even though some aspects have not been solved yet. This paper presents a simple design procedure for center-pivot systems using a gradually decreasing sprinkler spacing along with a pivot lateral, which makes it possible to set favorable and uniformly distributed water application r…