Measurement and Modeling of Ground-Level Ozone Concentration in Catania, Italy using Biophysical Remote Sensing and GIS

This experimental study examined spatial variation of ground level ozone (O3) in the city of Catania, Italy using thirty passive samplers deployed in a 500-m grid pattern. Significant spatial variation in ground level O3 concentrations (ranging from 12.8 to 41.7 g/m3) was detected across Catania’s urban core and periphery. Biophysical measures derived from satellite imagery and built environment characteristics from GIS were evaluated as correlates of O3 concentrations. A land use regression model based on four variables (land surface temperature, building area, residential street length, and distance to the coast) explained 74% of the variance (adjusted R2) in measured O3. The results of the study suggest that biophysical remote sensing variables are worth further investigation as predictors of ground level O3 (and potentially other air pollutants) because they provide objective measurements that can be tested across multiple locations and over time

performance analysis of biofuel fed gas turbine

Abstract The present paper deals with the study of the performance of a heavy-duty gas turbine running on biofuels. In particular, synthesis gas from glycerol steam reforming was used to feed the combustion turbine. Engine performances were compared with methane fed ones. Therefore, a mathematical model of the gas turbine was implemented using GateCycle software. Model calibration was made using gas turbine on-design parameters, while performance test results were compared with experimental running data. The resulting analysis highlighted that the mathematical model is able to correctly simulate engine behaviour in different combustion turbine running conditions thus validating the mathematical model. The combustion turbine studied was integrated with a syngas generator plant and overall efficiency was evaluated. The analysis of the results confirms that using biofuels a reduction in engine performance occurs. On the contrary, integrating the gas turbine and syngas generator plant an overall efficiency increase was registered

on the turbine induced damping in oscillating water column wave energy converter

Abstract The present paper deals with a study of the damping induced by a turbine in the power take off of an small scale Oscillating Water Column Wave Energy Converter. In order to study the turbine-induced damping, an experimental setup was built. The experimental setup consists of a wave flume 2000 mm long, 190 mm high and 96 mm wide with an impermeable beach as a dissipative system at the end to avoid wave reflections. The system is all built in Plexiglas to allow optical real-time observation. An Oscillating Water Column chamber model was placed in the measurement area between the wave-maker and the dissipative beach. The chamber was 37 mm long, 200 mm high and 96 mm wide also built in Plexiglas. In order to study the effect of turbine-induced damping on the system, a calibrated and variable hole was used to simulate the turbine presence, while outflow and inflow air velocity were measured by means of Particle Image Velocimetry (PIV) method. Pressures and velocities of air and water as well as the free water surfaces evolution were measured at different wave frequencies and heights

on the wind turbine wake mathematical modelling

Abstract The present paper deals with a study on the wind turbine wake mathematical modelling as well as experimental validation by means of wind tunnel experiments. In particular, different wind turbine wake's equations were implemented and results compared with experimental data. Therefore, an experimental setup was implemented in the wind tunnel test section with a small-scale wind turbine, while velocity deficit was measured. A design of experiment based on three parameters variation was defined: wind velocity, turbine rotational speed and distance from the wind turbine rotor. In the same experimental conditions simulations were carried out by means of three 1D equations. In particular, Jensen, Larsen and Frandsen equations were studied. Comparing theoretical and experimental results, it is evident that Larsen mathematical model is in good agreement with experimental data, while Jensen and Frandsen mathematical models are able to identify only mean and peak velocity deficit, respectively

Effects of low-grade gas composition on the energy/exergy performance of a polygeneration system (CH2HP) based on biomass gasification and ICE

Bio-hydrogen from sustainable biomass (i.e. agro-industrial residues) gasification can play a relevant role in the hydrogen economy, providing constant hydrogen from renewable sources. Nowadays, most hydrogen production systems integrate one or more water-gas shift (WGS) units to maximize the hydrogen yield that, however, needs additional syngas treatments, investment and operational costs. Besides, different electricity inputs are needed along the process to power the compression of raw syngas, shifted syngas, and pure hydrogen to the desired pressure. This common process integration with WGS generates a kind of off-gas from the hydrogen separation unit whose composition may or may not be suitable for power production, depending on the operating conditions of the gasification unit. In this regard, this work proposes a different approach in which no WGS reactors are involved and the off-gas is used to generate heat and power to provide the energy input needed by the system. In particular, the authors tested the bio-syngas and the corresponding off-gas in a 4-cylinders, spark ignition natural gas internal combustion engine operated in cogeneration mode with the aim to analyse the effect of removing the hydrogen from the original bio-syngas on mechanical/electric and thermal power, on fuel efficiency and CO2 specific emission

On the use of dynamic reliability for an accurate modelling of renewable power plants

Renewable energies are a key element of the modern sustainable development. They play a key role in contributing to the reduction of the impact of fossil sources and to the energy supply in remote areas where the electrical grid cannot be reached. Due to the intermittent nature of the primary renewable resource, the feasibility assessment, the performance evaluation and the lifecycle management of a renewable power plant are very complex activities. In order to achieve a more accurate system modelling, improve the productivity prediction and better plan the lifecycle management activities, the modelling of a renewable plant may consider not only the physical process of energy transformation, but also the stochastic variability of the primary resource and the degradation mechanisms that affect the aging of the plant components resulting, eventually, in the failure of the system. This paper presents a modelling approach which integrates both the deterministic and the stochastic nature of renewable power plants using a novel methodology inspired from reliability engineering: the Stochastic Hybrid Fault Tree Automaton. The main steps for the design of a renewable power plant are discussed and implemented to estimate the energy production of a real photovoltaic power plant by means of a Monte Carlo simulation process. The proposed approach, modelling the failure behavior of the system, helps also with the evaluation of other key performance indicators like the power plant and the service availability

Functional Changes in the Snail Statocyst System Elicited by Microgravity

BACKGROUND: The mollusk statocyst is a mechanosensing organ detecting the animal's orientation with respect to gravity. This system has clear similarities to its vertebrate counterparts: a weight-lending mass, an epithelial layer containing small supporting cells and the large sensory hair cells, and an output eliciting compensatory body reflexes to perturbations. METHODOLOGY/PRINCIPAL FINDINGS: In terrestrial gastropod snail we studied the impact of 16- (Foton M-2) and 12-day (Foton M-3) exposure to microgravity in unmanned orbital missions on: (i) the whole animal behavior (Helix lucorum L.), (ii) the statoreceptor responses to tilt in an isolated neural preparation (Helix lucorum L.), and (iii) the differential expression of the Helix pedal peptide (HPep) and the tetrapeptide FMRFamide genes in neural structures (Helix aspersa L.). Experiments were performed 13-42 hours after return to Earth. Latency of body re-orientation to sudden 90° head-down pitch was significantly reduced in postflight snails indicating an enhanced negative gravitaxis response. Statoreceptor responses to tilt in postflight snails were independent of motion direction, in contrast to a directional preference observed in control animals. Positive relation between tilt velocity and firing rate was observed in both control and postflight snails, but the response magnitude was significantly larger in postflight snails indicating an enhanced sensitivity to acceleration. A significant increase in mRNA expression of the gene encoding HPep, a peptide linked to ciliary beating, in statoreceptors was observed in postflight snails; no differential expression of the gene encoding FMRFamide, a possible neurotransmission modulator, was observed. CONCLUSIONS/SIGNIFICANCE: Upregulation of statocyst function in snails following microgravity exposure parallels that observed in vertebrates suggesting fundamental principles underlie gravi-sensing and the organism's ability to adapt to gravity changes. This simple animal model offers the possibility to describe general subcellular mechanisms of nervous system's response to conditions on Earth and in space

Passenger Car Energy Demand Assessment: a New Approach Based on Road Traffic Data

Nowadays the automotive market is oriented to the production of hybrid or electric propulsion vehicle equipped with Energy Management System that aims to minimize the consumption of fossil fuel. The EMS, generally, performs a local and not global optimization of energy management due to the impossibility of predicting the user’s energy demand and driving conditions. The aim of this research is to define a driving cycle (speed time) knowing only the starting and the arrival point defined by the driver, considering satellite data and previous experiences. To achieve this goal, the data relating to the energy expenditure of a car (e.g. speed, acceleration, road inclination) will be acquired, using on-board acquisition system, during road sections in the city of Messina. At the same time, the traffic level counterplot and others information provided, for these specific sections, from GPS acquisition software will be collected. On-board and GPS data will be compared and, after considering an adequate number of acquisitions, each value of the traffic level will be associated with a driving cycle obtained by processing the acquired data. After that, the numerical model of a car will be created which will be used to compare the energy demand of two driving cycles. The first one acquired on a section with a random starting and destination point inside the historic city centre of Messina. The second is the one assigned, for that same section, considering only the value of the traffic level counterplot