0000000000464725
AUTHOR
P. Zuddas
showing 9 related works from this author
Geochemistry of Zr, Hf, and REE in a wide spectrum of Eh and water composition: The case of Dead Sea Fault system (Israel)
2017
International audience; Along the Jordan Valley-Dead Sea Fault area several natural waters in springs, wells, and catchments occur. The chemical-physical characters of the studied waters allowed for the first time the investigation of the Zr and Hf geochemical behavior, apart from REE, extended to a wide range of Eh, temperature, salinity, and pH conditions. The results of this study indicate that the dissolved Zr and Hf distribution in natural waters is strongly influenced by redox conditions since these in turn drive the deposition of Fe-oxyhydroxides or pyrite. In oxidizing waters saturated or oversaturated in Fe-oxyhydroxides (Group 1), superchondritic Zr/Hf values are measured. On the …
Anomalous Behavior of Zirconium and Hafnium in Volcanic Fumarolic Fluids
2022
The Zirconium and Hafnium concentrations in worldwide fumaroles fed by magmatic fluids reveal that the Zr/Hf ratio is inversely related to the temperature of emission. Lower Zr/Hf ratio values below the chondritic signature are found in fluids having the highest temperature while super-chondritic Zr/Hf ratio values are found in lower temperatures. Sub-chondritic values of the Zr/Hf ratio may be related to larger volatility of Hf-chloride gas species with respect to Zr-Cl gas species, while super-chondritic ratios may correspond to fluid-rock processes resulting from cooling of uprising magmatic fluids. We propose that subchondritic Zr/Hf ratio values in fumaroles associated with high temper…
AN OPTIMIZATION MODEL FOR DAILY MANPOWER ALLOCATION IN TRANSSHIPMENT CONTAINER TERMINALS
2011
This work is motivated by the manpower allocation problem arising at the Cagliari International Terminal Container. Generally speaking, human resources allocation plays a key role in terminals with high labor costs, in order to achieve high levels of productivity and quality services for customers. As a result, terminal containers exhibit a growing interest in advanced decision support systems, in which optimization methods play a crucial role. In this talk we present an optimization model for manpower allocation in transshipment container terminals. The objective is to determine the optimal daily allocation of crane operators and trailer drivers at an operational planning level, taking int…
An optimisation model for daily manpower allocation in transhipment container terminals
2011
This work is motivated by the manpower allocation problem arising at the Cagliari International Terminal Container. Generally speaking, human resources allocation plays a key role in terminals with high labor costs, in order to achieve high levels of productivity and quality services for customers. As a result, terminal containers exhibit a growing interest in advanced decision support systems, in which optimization methods play a crucial role. In this talk we present an optimization model for manpower allocation in transshipment container terminals. The objective is to determine the optimal daily allocation of crane operators and trailer drivers at an operational planning level, taking int…
Authigenic phases and biomass contents drive Zr, Hf and REE distributions in anoxic lake sediments.
2013
Abstract. REE, Zr and Hf distributions in seafloor sediments collected from the hypersaline, anoxic Thetis, Kryos, Medee and Tyro deep-sea basins from the Eastern Mediterranean were determined in light of their mineralogical composition, and biomass contents. Mineralogical investigations demonstrate that all the studied sediments show a similar mineralogy. Detritic assemblages mainly consist of quartz, gypsum and calcite with Mg contents ranging from 0 to about 7%, often of a bioclastic nature. On the contrary, authigenic parageneses are formed by halite, bischofite, dolomite and calcite, with Mg contents up to 22%. Textural evidences of biological activity were also identified. In sediment…
Rare earths release from dissolving atmospheric dust and their accumulation into crystallising halite. The dead-sea example
2023
: The industrial extraction of Y and lanthanides (hereafter defined as Rare Earth Elements, REE) often requires the achievement of leaching procedures removing these metals from primary rocks and their transfer in aqueous leachates or incorporated in newly forming soluble solids. These procedures are the most dangerous to the environment in relation to the composition of leachates. Hence, the recognition of natural settings where these processes currently occur, represents a worthy challenge for learning how to carry out similar industrial procedures under natural and more eco-friendly conditions. Accordingly, the REE distribution was studied in the brine of Dead Sea, a terminal evaporating…
Human Resource Allocation for Maritime Container Terminals: E ects of Planning Horizon Length
2012
The human resources allocation (HRA) is a major issue for container terminals. The workload is organized in shifts covering 24 hours a day and, due to union and work rules, shifts are typically requested to be planned a number of months before their implementation. As a consequence, information on the workforce demand is imprecise when HRA must be planned. This problem must be addressed by a superior exibility, which can be achieved by the two planning levels: the long term stage and the short term one, which encompasses one or more days. In this talk we address the operational planning level which inherits some unchangea- ble decisions from the long term plan and considers the terminal res…
Boron and lithium behaviour in river waters under semiarid climatic conditions
2022
Boron (B) and Lithium (Li) concentrations were studied in the Platani river, one of the most important catchments of South-Central Sicily which is under semiarid climatic conditions for roughly eight months to a year. In this area, evaporites result in potential B and Li sources for surface waters. Results from river waters have measured ionic strength values between 0.1 and 4.54 M. B and Li distributions in these waters were studied in colloidal (CF, extracted by ultrafiltration from the 0.45 μm filtrate) and total dissolved (TDF) fractions and in fractions extracted from corresponding riverbed sediments, according to changes of the B/Li ratio. In river waters, CF and TDF showed very simil…
Modeling Human Resources Management in Maritime Container Terminals
2012
Over the last few decades, competition among maritime container terminals has increased due to large growth rates on major seaborne container routes. Thus terminals have to carefully plan the management of their facilities and services in order to satisfy shipping companies’ demands. Failure to do so will lead customers to re-schedule their routes calling at new promising terminals. As a result, and so as not to lose competitiveness, container terminals are showing a growing interest in advanced decision support systems for their management, in which optimization methods play a crucial role. In this context, the optimal management of human resources is a major issue for terminals, particula…