Optimum sizing of cogeneration plants by means of a genetic algorithm optimization: A case study

In the context of increasing energy consumption, multi-generation systems such as combined heat and power generation (CHP) are attractive to meet the increasingly stringent requirements regarding energy saving in buildings. Hospitals are great consumers of energy, both electrical and thermal: the use of heating and cooling equipment for maintaining satisfactory comfort and indoor air quality for the patients as well as the adoption of several electrical health equipment result in the highest energy consumption per unit floor area of the entire building sector. In the present study, co/tri-generation systems\u2019 optimal set-up, size and operation are investigated for small/medium size hospital facilities. More specifically, after the presentation of the energy consumption profiles for a medium size hospital with 600 beds, set as reference case for this study, a parametric analysis has been carried out varying the peak loads of the user. For each of the proposed scenarios, the optimal plant configuration (sizing of all the energy production systems) has been outlined by means of a numerical code (Trigen 3.0) in-house developed. Afterwards, in order to optimize the load distribution in a smart grid characterized by electrical, thermal, cooling and fuel energy fluxes, an ulterior numerical investigation has been performed. The software, named EGO (Energy Grids Optimizer) consists of a genetic algorithm procedure: it defines the optimal load distribution of a number of energy systems operating into a smart grid based on the minimization of an objective function which expresses the total cost of energy production. Finally, an economic analysis has been carried out in order to evaluate the profitability of the proposed CHP-heat pump scenario

Selective detection of liposoluble vitamins using an organic electrochemical transistor

Accurate quantification of vitamins content is essential in food analysis, with direct impact on the quality of our diet and, therefore, on our health. Current research interest is devoted to the design of robust and versatile devices able to perform real-time analyses that do not strictly rely on laboratory facilities. Here, we report the first organic electrochemical transistor (OECT) based sensor working in organic environment for the detection of a fat-soluble vitamin (Vitamin A). The OECT behaviour in organic solvents was thoroughly characterized and its structure was optimised allowing both potentiostatic and potentiodynamic detections. On one hand, the potentiostatic approach provided a gain of 100 and the detection limit was as low as 115 nM, but it did not address selectivity issues. On the other hand, the potentiodynamic approach showed a higher detection limit, but allowed the selective detection of Vitamin A in the presence of & alpha;-Tocopherol. Analyses of randomized solutions revealed that a pre-calibrated sensor can estimate Vitamin A concentration with a 3% error. Moreover, the robustness of our sensor was demonstrated by analysing commercial food fortifiers without any sample pretreatment

A polymeric mixed conductor-based solid state charge storage device †

Organic mixed ionic and electronic conductors (OMIECs) are soft materials capable of reversibly storing electronic charges in their bulk, stabilized by ionic charges typically introduced from an electrolyte. Recent advancements in OMIEC design have improved their ion uptake and transport properties, increasing the number of charges stored per monomer unit, thus making them attractive candidates for charge storage devices. However, the use of aqueous electrolytes, common in OMIEC based systems, limit storage performance due to their narrow voltage window. In this work, we introduce an OMIEC-based charge storage device that operates with an ionic liquid gel electrolyte serving as a transparent, solid-state ion reservoir within a full-cell package. This design allows stable operation up to 2.4 V and integrates an embedded failure diagnostics system. To address the critical issue of self-discharge, we incorporated an O2 and H2O barrier into the device, significantly improving its performance under ambient conditions. This cell design enables standardized conditions for screening OMIECs, eliminating interference from parasitic reactions or electrolyte instability. Using this system, we systematically evaluated a range of n-type OMIECs and identified the optimal anode material. The resulting device demonstrated a capacity of ∼25 mA h g−1 and an energy density of ∼118 W h kg−1, surpassing the performance of existing OMIEC-based systems. This work represents a step toward safer and more efficient polymer-based charge storage technologies

Reconfiguration of organic electrochemical transistors for high-accuracy potentiometric sensing

Organic electrochemical transistors have emerged as a promising alternative to traditional 2/3 electrode setups for sensing applications, offering in-situ transduction, electrochemical amplification, and noise reduction. Several of these devices are designed to detect potentiometric-derived signals. However, potentiometric sensing should be performed under open circuit potential conditions, allowing the system to reach thermodynamic equilibrium. This criterion is not met by conventional organic electrochemical transistors, where voltages or currents are directly applied to the sensing interface, that is, the gate electrode. In this work, we introduce an organic electrochemical transistor sensing configuration called the potentiometric‑OECT (pOECT), which maintains the sensing electrode under open circuit potential conditions. The pOECT exhibits a higher response than the 2-electrode setup and offers greater accuracy, response, and stability compared to conventional organic electrochemical transistors. Additionally, it allows for the implementation of high-impedance electrodes as gate/sensing surfaces, all without compromising the overall device size

Relation between Indoor and Outdoor Exposure to Fine Particles Near a Busy Arterial Road

Various studies on indoor and outdoor particulate matter in the urban environment in the vicinity of busy arterial roads in the centre of the subtropical city of Brisbane have indicated that the revised United States Environmental Protection agency National Ambient air Quality Standards for Particulate matter PM2.5 could be exceeded not only outdoors but also indoors. The aim of this work was to investigate outdoor exposure to submicrometer particles and their relationship with indoor exposure in a hypothetical office building located in the vicinity of a busy arterial road. The outdoor exposure values and trends were measured in terms of particle number in the submicrometer size range and were then recalculated to represent mass concentration trends. The results of this study indicate that exposure to PM0.7 particles in ambient air close to a busy road often exceeds the levels of the annual and 24-hour US EPA NAAQS PM2.5 standards. It is likely that exposure to PM2.5 is even higher, and may significantly exceed these standards

Un nuovo futuro: sciami di droni

Al giorno d’oggi, i droni hanno molti nuovi ruoli sia nel settore pubblico che in quello privato, nei settori del commercio, dell’ambiente, dell’agricoltura e della sorveglianza. Sono spesso utilizzati in compiti specifici come rilevamento, localizzazione, trasporto, sicurezza, ricerca e salvataggio e tanto altro. In generale, i droni raccolgono periodicamente delle informazioni non elaborate sull’ambiente e inviano i dati al centro di controllo che permette di gestire i droni ed elaborare i dati in ricezione. Uno sciame o flotta di droni, è invece un insieme di UAV che cooperano tra di loro per raggiungere un obbiettivo specifico in comune. Ogni drone all'interno di uno sciame è azionato da un certo numero di rotori e ha le capacità di librare, decollare e atterrare verticalmente. Mentre i droni sono stati utilizzati nelle operazioni di salvataggio già da anni, l'invio di sciami con droni più piccoli potrebbe salvare ancora più vite. L'utilizzo di sciami può anche permettere di semplificare molti compiti che riguardano l'agricoltura, la manutenzione, il monitoraggio e tanto altro. L'intelligenza dello sciame sta ricevendo molta attenzione da parte della ricerca negli ultimi anni. Per questo motivo il documento tratterà i droni partendo da una panoramica su di essi, in cui si ha lo scopo di offrire una prima conoscenza di base. Dopodiché ci si concentrerà di più sugli sciami di droni che, dato all'incremento del numero di velivoli all'interno dello sciame necessitano di tecniche adeguate per la comunicazione autonoma tra i droni, per problemi riguardante sicurezza e privacy dei dati e per meccanismi che consentano di evitare collisioni tra droni. Inoltre, data la notevole difficoltà in fase di progettazione, vengono anche mostrati alcuni simulatori per sviluppare i droni in modo del tutto sicuro

Sviluppo di transistor elettrochimici per la determinazione di vitamine liposolubili in solvente organico

Il lavoro qui presentato ha riguardato lo sviluppo di un sensore elettrochimico per la determinazione di vitamine liposolubili in ambiente organico. Il dispositivo sviluppato presenta la struttura di base di un transistor elettrochimico organico (OECT) che è stato adattato, a seguito di modifiche strutturali, per la determinazione (i) di retinil acetato e retinil palmitato all’interno di una miscela di etanolo – acetonitrile 1:1, (ii) per condizioni analoghe alle precedenti ma in presenza anche di α-tocoferolo come interferente. Infine sono state studiate anche ulteriori modifiche alla struttura dell’OECT impiegando più dispositivi contemporaneamente, per incrementare l’efficienza del sensore

Violazione della sicurezza di rete tramite costruzione di pacchetti anomali

La sicurezza informatica è la pratica di proteggere i sistemi critici e le informazioni sensibili dagli attacchi digitali. Note anche come sicurezza IT, le misure della sicurezza informatica sono progettate per combattere le minacce contro sistemi in rete e applicazioni, che hanno origine sia all’interno che all’esterno di un’organizzazione. Al giorno d'oggi, la minaccia informatica globale continua a evolversi ad un ritmo rapido, con un numero crescente di violazioni dei dati ogni anno. Lo scopo di questo documento è di offrire inizialmente una panoramica su quelli che sono i contesti della sicurezza informatica e le varie tipologie di attacco, per poi mostrare, attraverso la realizzazione di tre casi d'uso, delle modalità con cui violare la sicurezza di una rete tramite costruzione di pacchetti ARP anomali sfruttando l'utilizzo della libreria Scapy. La prima di queste simulerà una casistica di attacco noto come ARP Spoofing dove si tenta di andare ad avvelenare la tabella ARP di un host. Il secondo caso d'uso genera dei pacchetti ARP anomali con all'interno del payload relativo a datagrammi UDP o segmenti TCP causando un possibile sovraccarico della rete, potendo perciò simulare degli attacchi DoS. Il terzo e ultimo caso d'uso genera uno scambio di informazioni ARP tra host di due LAN differenti attraverso l'uso di pacchetti TCP o UDP creando una specie di tunneling tra i due host. I risultati finali permettono di verificare che tramite l'utilizzo di un semplice protocollo come ARP, si possano in realtà generare nuove modalità con cui minacciare la sicurezza informatica. Questo ci fa quindi dedurre la possibilità di poter creare numerose metodologie di attacco, utilizzando la vastità di protocolli utilizzati nelle reti, confermando che il cybercrimine è sempre in continua evoluzion

Control Strategies for Sub-Micrometer Particles Indoors: Model Study of Air Filtration and Ventilation

The effects of air filtration and ventilation on indoor particles were investigated using a single-zone mathematical model. Particle concentration indoors was predicted for several I/O conditions representing scenarios likely to occur in naturally and mechanically ventilated buildings. The effects were studied for static and dynamic conditions in a hypothetical office building. The input parameters were based on real-world data. For conditions with high particle concentrations outdoors, it is recommended to reduce the amount of outdoor air delivered indoors and the necessary reduction level can be quantified by the model simulation. Consideration should also be given to the thermal comfort and minimum outdoor air required for occupants. For conditions dominated by an indoor source, it is recommended to increase the amount of outdoor air delivered indoors and to reduce the amount of return air. Air filtration and ventilation reduce particle concentrations indoors, with the overall effect depending on efficiency, location and the number of filters applied. The assessment of indoor air quality for specific conditions could be easily calculated by the model using user-defined input parameters

The stochastic modeling of random wake past a circular cylinder

We study the random laminar wake past a circular cylinder corresponding to a random Reynolds number. The random flow is computed using two different stochastic methods, i.e. the generalized polynomial chaos and the multi-element generalized polynomial chaos method. Rigorous convergence to the correct statistics of the velocity field is established. The random flow is subsequently decomposed into random modes according to a new type of orthogonal decomposition developed in this paper. This orthogonal decomposition which is substantially built upon the proper orthogonal decomposition framework defines an optimal set of random projectors for the stochastic Navier-Stokes equations which, after a suitable averaging operation, leads to a deterministic temporal evolution, i.e. a system of ordinary deterministic differential equations. This allow to construct a reduced order Galerkin model of the random flow as superimposition of deterministic temporal evolution of random spatial structures. Numerical applications are presented and discussed