Search results for "Availability"
showing 10 items of 510 documents
Load Response and Finite Element Modelling of Bonded Loading Hoses
2014
Steel reinforced bonded vulcanized rubber loading hoses are frequently used in offshore oil loading systems. The hoses are used as offloading system between platforms and shuttle tankers and represent a flexible economical feasible solution for hydrocarbon transfer. The reliability of these hoses throughout the service life is an important issue both with respect to operational availability and with respect to environmental safety. Hence, the load bearing capacity of these hoses and the fatigue endurance become matters of concern and important design topics. Due to the large deformation of these hoses and the complicated composite structure in the hose wall, the hoses are difficult to analy…
A Multi-Objective Approach to Optimize a Periodic Maintenance Policy
2012
The present paper proposes a multi-objective approach to find out an optimal periodic maintenance policy for a repairable and stochastically deteriorating multi-component system over a finite time horizon. The tackled problem concerns the determination of the system elements to replace at each scheduled and periodical system inspection by ensuring the simultaneous minimization of both the expected total maintenance cost and the expected global system unavailability time. It is assumed that in the case of system elements failure they are instantaneously detected and repaired by means of minimal repair actions in order to rapidly restore the system. A nonlinear integer mathematical programmi…
Analysis, Modeling and Simulation of Complex Regional Clusters Activities, Using Arena Simulation Software
2014
Process modelling is the concise description of the total variation in one quantity, y, by partitioning it into a deterministic component given by a mathematical function of one or more other quantities, x1, x2... plus a random component that follows a particular probability distribution. The models are material or immaterial systems, which represent other systems, so that it may be possible to manipulate the built structures and their states. The main elements of a simulation are: attributes (describe and differentiate entities), variables (system characteristics), resources (whose capacity can be variable), tails (seen in case of unavailability of resources) and statistical accumulators (…
Antiviral capacity of sanitizers against infectious viruses in process water from the produce industry under batch and continuous conditions
2023
The presence of human enteric viruses in produce has extensively been reported. However, the significance of the quality of process water (PW) used by the produce industry and the viral inactivation capacity of water disinfection agents used to maintain the microbiological quality of PW has received limited attention. This study evaluates the antiviral disinfection efficacy of chlorine, chlorine dioxide (ClO2) and peracetic acid (PAA) at recommended operational limits in PW using hepatitis A virus (HAV), the cultivable norovirus surrogate, murine norovirus (MNV-1), and MS2 coliphages. Defined commodity representative crops (baby leaves, bell peppers, and the vegetable mix of tomatoes, cucum…
A preliminary study on the ecotoxic potency of wastewater treatment plant sludge combining passive sampling and bioassays.
2021
Highlights • The passive samplers collected bioavail able and bioaccessible chemicals from the WWTP sludge samples. • The sampler extracts were acutely and chronically toxic to water flea. • The sampler extracts were cytotoxic and genotoxic. • The sludge treatment such as composting and digesting diminished the toxicity. • Effect-based methods should be part of the risk assessment of sludge recycling. Sewage sludge is an inevitable byproduct produced in wastewater treatment. Reusing nutrient-rich sludge will diminish the amount of waste ending in soil dumping areas and will promote circular economy. However, during sewage treatment process, several potentially harmful organic chemicals are …
Impact of historical mining assessed in soils by kinetic extraction and lead isotopic ratios.
2014
12 pages; International audience; The aim of this study is to estimate the long-term behaviour of trace metals, in two soils differently impacted by past mining. Topsoils from two 1 km(2) zones in the forested Morvan massif (France) were sampled to assess the spatial distribution of Cd, Cu, Pb and Zn. The first zone had been contaminated by historical mining. As expected, it exhibits higher trace-metal levels and greater spatial heterogeneity than the second non-contaminated zone, supposed to represent the local background. One soil profile from each zone was investigated in detail to estimate metal behaviour, and hence, bioavailability. Kinetic extractions were performed using EDTA on thre…
Trace metal(loid) mobility in waste deposits and soils around Chadak mining area, Uzbekistan
2017
Abstract The assessment of potential trace metal(loid) contamination in tailing dumps and soils was characterized in the Chadak mining area (Uzbekistan). Concentrations of trace elements (V, Cr, Co, Ni, Cu, Zn, As, Cd, Sb, Pb) were determined by X-ray fluorescence analysis and compared with background and intervention values (IV). The concentrations of As, Zn, Sb, and Pb were higher in the abandoned than in the active tailing dump, ranging from 42–1689 mg/kg for As, 73–332 mg/kg for Zn, 14–1507 mg/kg for Sb, and 27–386 mg/kg for Pb. Selective extractions were applied in order to assess the mobility and availability of trace metal(loid)s in samples. Oxyanion-forming elements such as As and S…
Spontaneous ecological recovery of vegetation in a red gypsum landfill: Betula pendula dominates after 10 years of inactivity
2019
International audience; Red gypsum is the product of the neutralization of titanium dioxide (TiO 2) extraction residue from ilmenite and anatase. The disposal of red gypsum creates heterogeneous plots with layers that may include Fe, Ca, Al, Mg, Mn, S, and other elements and an alkaline pH that makes revegetation complicated and slow. The vertical and horizontal dispersion of the sediment particles are the main concern. Therefore, the establishment of precise vegetation cover is needed to address this issue. One of the aims of this study was (1) to explore the distribution of the spontaneous vegetation found along a red gypsum-formed landfill located at the Ochsenfeld site in eastern France…
Long-term effect of temperature on bioaccumulation of dietary metals and metallothionein induction in Sparus aurata
2012
Previous studies have demonstrated that the commercial feed of aquacultured fish contains trace amounts of toxic and essential metals which can accumulate in tissues and finally be ingested by consumers. Recently rising temperatures, associated to the global warming phenomenon, have been reported as a factor to be taken into consideration in ecotoxicology, since temperature-dependent alterations in bioavailability, toxicokinetics and biotransformation rates can be expected. Sparus aurata were kept at 22. °C, 27. °C and 30. °C for 3. months in order to determine the temperature effect on metallothionein induction and metal bioaccumulation from a non-experimentally contaminated commercial fee…
Trace metals supplementation in anaerobic membrane bioreactors treating highly saline phenolic wastewater
2017
Biomass requires trace metals (TM) for maintaining its growth and activity. This study aimed to determine the effect of TM supplementation and partitioning on the specific methanogenic activity (SMA), with a focus on cobalt and tungsten, during the start-up of two lab-scale Anaerobic Membrane Bioreactors (AnMBRs) treating saline phenolic wastewater. The TM partitioning revealed a strong accumulation of sodium in the biomass matrix and a wash-out of the majority of TM in the reactors, which led to an SMA decrease and a low COD removal of about 30%. The SMA exhibits a maximum at about 6 g Na+ L−1 and nearly complete inhibition at 34 g Na+ L−1. The dose of 0.5 mg L−1 of tungsten increases the …