Search results for "Aggregate"
showing 10 items of 287 documents
Improvements in aggregate-paste interface by the hydration of steelmaking waste in concretes and mortars
2019
[EN] The objective of the experimental work is to study the mechanical properties in self-compacting concretes (SCC) in which part of the limestone aggregate has been replaced by granulated blast furnace slag (GBFS) in different percentages ranging from 0% to 60%. The results show that at early ages the SCC with the largest content in slag tend to have lower compressive strengths due to the poor compacting of the aggregates, although in the long-term their strength increases due to the reactivity of the slag. In fact, at the age of 365 days, the mortars made with the substitution of 50% of cement by ground GBFS reach compressive strength similar to that of the mortar made with 100% of cemen…
Greedy versus Dynamic Channel Aggregation Strategy in CRNs: Markov Models and Performance Evaluation
2011
Part 1: - PE-CRN 2011 Workshop; International audience; In cognitive radio networks, channel aggregation techniques which aggregate several channels together as one channel have been proposed in many MAC protocols. In this paper, we consider elastic data traffic and spectrum adaptation for channel aggregation, and propose two new strategies named as Greedy and Dynamic respectively. The performance of channel aggregation represented by these strategies is evaluated using continuous time Markov chain models. Moreover, simulation results based on various traffic distributions are utilized in order to evaluate the validity and preciseness of the mathematical models.
Endodontic management of type II dens invaginatus with open apex and large periradicular lesion using the XP-endo Finisher : a case report
2018
Dens invaginatus (DI) represents an endodontic challenge because of its complex root canal morphology. This case report presents the clinical management of a 22-year-old woman with type II DI in right maxillary lateral incisor with a painful swelling. Pulp testing revealed no response with the tooth. Type II DI with open apex and large periradicular lesion was seen on radiograph. The treatment was planned by using cone-beam computed tomography (CBCT) imaging. Canal treatment was completed in two appointments with the aid of a dental operating microscope. In the first appointment, the internal anatomy was modified using an ultrasonic tip, and chemo-mechanical preparation was performed using …
Can the Students’ Career be Helpful in Predicting an Increase in Universities Income?
2013
The students’ academic failure and the delay in obtaining their final degree are a significant issue for the Italian universities and their stakeholders. Based on indicators proposed by the Italian Ministry of University, the Italian universities are awarded a financial incentive if they reduce the students’ attrition and failure. In this paper we analyze the students’ careers performance using: (1) aggregate data; (2) individual data. The first compares the performances of the Italian universities using the measures and the indicators proposed by the Ministry. The second analyzes the students’ careers through an indicator based on credit earned by each student in seven academic years. The …
Characterization of a small Mediterranean island end-users’ electricity consumption: The case of Lampedusa
2017
Abstract The paper presents the results of a study carried out on Lampedusa Island (Italy) and based on the survey of electricity consumption data. The main outcomes of the study are: • the characterization of the energy demand of private houses and hotels in Italian small islands with significant touristic flows during the summer period; • the identification of inefficient use of the electric loads; • the construction of aggregated load profiles for clusters of homogeneous domestic end-user to be used for implementing Demand Response strategies. The study shows how electricity consumption in Mediterranean small islands are very high with respect to the national average and lays the basis f…
SOIL QUALITY INDICATORS AS AFFECTED BY SHALLOW TILLAGE IN A VINEYARD GROWN IN A SEMIARID MEDITERRANEAN ENVIRONMENT
2016
Within the Mediterranean basin, soil tillage enhances the mineralisation of soil organic matter. We assessed the short-term impact of shallow tillage [field cultivator (FC), rotary tiller (RT) and spading machine (SM)] on some soil quality indicators [bulk density, water-stable aggregates, total and labile organic C pools (microbial biomass and extractable organic C), soil respiration and related eco-physiological indexes] in a Sicilian vineyard. Also no tillage was included. We hypothesized that (i) RT and FC worsened soil quality indicators more than SM, and (ii) within the same tillage system, labile C pools, soil respiration and eco-physiological indexes will respond more efficiently th…
A FE-Meshless Multiscale Approach for Masonry Materials
2015
Abstract A FE-Meshless multiscale computational strategy for the analysis of running bond masonry is presented. The Meshless Method (MM) is adopted to solve the boundary value problem (BVP) at the mesoscopic level. The representative unit cell is composed by the aggregate and the surrounding joints, the former assumed to behave elastically while the latter are simulated as non-associated elastic-plastic zero-thickness interfaces with a softening response. Macroscopic localization of plastic bands is obtained performing a spectral analysis of the tangent stiffness matrix. Localized plastic bands are embedded into the quadrature points area of the macroscopic finite elements.
Utilization of microbial abundance and diversity as indicators of the origin of soil aggregates produced by earthworms
2013
This study aimed at testing the capability of microbial community structure and abundance to be used as bioindicators of the origin of earthworm cast aggregates. Compact surface casts produced by Amynthas khami and surrounding aggregates lacking visible signs of biological activity (control) were left to disaggregate by natural rainfall and separated into four size classes (5-2, 2-0.5, 0.5-0.25 and <0.25 mm). The genetic structure and the abundance of the bacterial and fungal communities were characterized using B- and F-ARISA fingerprinting approach and quantitative PCR directly from DNA extracted from soil. Bacteria and to a lesser extent fungi were more abundant in casts than in control …
Is ex‐ante ex‐post analysis irrelevant to Keynes's theory of employment?
2004
Ex‐ante ex‐post analysis has become a standard tool in macroeconomics. Yet Keynes dismissed it. We argue that Keynes's dismissal of ex‐ante ex‐post analysis is not an oddity but an indication of the originality of his theory of employment compared to standard macroeconomics. First, the principle of effective demand does not amount to a process that determines employment and income at the point of intersection of the traditionally defined ex ante supply and demand functions. Second, the finance motive allowed Keynes to confirm the identity of aggregate supply and demand already asserted in The General Theory. This latter conclusion is puzzling, however, since the principle of effective deman…
Traditional endodontic surgery versus modern technique: a 5-year controlled clinical trial.
2014
In this study, we compared outcomes of traditional apicoectomy versus modern apicoectomy, by means of a controlled clinical trial with a 5-year follow-up. The study investigated 938 teeth in 843 patients. On the basis of the procedure performed, the teeth were grouped in 3 groups. Differences between the groups were the method of osteotomy (type of instruments used), type of preparation of retrograde cavity (different apicoectomy angles and instruments used for root-end preparation), and root-end filling material used (gray mineral trioxide aggregate or silver amalgam). Outcome (tooth healing) was estimated after 1 and 5 years, postoperatively. Clinical success rates after 1 year were 67% (…