Assessment of a tunnel safety

LAUREA MAGISTRALELa valutazione dell'impatto della costruzione delle gallerie sulle strutture sopra il livello del suolo, nelle aree urbane, si basa fortemente sulle previsioni dell'assestamento a livello della superficie. È importante monitorare l'integrità e la salute delle gallerie e per farlo esistono molte tecniche. La tesi presenta un’analisi svolta durante uno stage in un'azienda di geofisica (Geosurveys srl), dove sono stato membro attivo del team tecnico. Questa mostra una rassegna dei metodi di prova e una classificazione delle strategie e degli strumenti in termini di tecnologie e tecniche applicate al monitoraggio delle gallerie. Insieme ai miei colleghi abbiamo svolto più rilievi: abbiamo applicato una serie di tecniche non distruttive al fine di trovare stabilità e integrita’ del tunnel; per trovare buchi all'interno del tunnel abbiamo eseguito esami videoendoscopici. I campioni di calcestruzzo raccolti sono stati inviati al laboratorio di prova. Questo documento descrive tutte le tecniche, la procedura di acquisizione e i risultati. Il flusso di lavoro può essere generalizzato a un "manuale di buone pratiche" per il monitoraggio dell'integrità del tunnel. Sulla base dell'analisi geofisica si sono riscontrate delle crepe nelle gallerie e lo studio si conclude con lo stato del calcestruzzo e le crepe e i buchi trovati nella galleria.Evaluating the impact of tunnelling on above ground structures in urban areas highly relies on predictions of the settlement through at surface level. It is important to monitor tunnels integrity and health. There exists many techniques to do that. The thesis presents a case history performed during an internship in a geophysical (Geosurveys srl) company, where I have been an active member of the technical team. It dispenses a review of testing methods and a classification of strategies and tools in terms of technologies and techniques applied to the monitoring of tunnels. Myself along with my colleagues have done multiple surveys. We have applied a set of non-destructive techniques, in order to find stability and strength of the tunnel. To find holes inside the tunnel, we performed videoendoscopic examinations. The samples of concrete which we gathered from the tunnel were dispatched to the laboratory test. This document describes all the techniques, the acquisition campaign, and the results. The work flow can be generalized to a “best practice manual” for monitoring tunnel integrity. Based on the geophysical analysis, we obtained the state of the concrete and the position of holes and cracks inside the tunnel

Bio-processing of algal bio-refinery: a review on current advances and future perspectives

Microalgae biomass contains various useful bio-active components. Microalgae derived biodiesel has been researched for almost two decades. However, sole biodiesel extraction from microalgae is time-consuming and is not economically feasible due to competitive fossil fuel prices. Microalgae also contains proteins and carbohydrates in abundance. Microalgae are likewise utilized to extract high-value products such as pigments, anti-oxidants and long-chain polyunsaturated fatty acids which are useful in cosmetic, pharmaceutical and nutraceutical industry. These compounds can be extracted simultaneously or sequentially after biodiesel extraction to reduce the total expenditure involved in the process. This approach of bio-refinery is necessary to promote microalgae in the commercial market. Researchers have been keen on utilizing the bio-refinery approach to exploit the valuable components encased by microalgae. Apart from all the beneficial components housed by microalgae, they also help in reducing the anthropogenic CO2 levels of the atmosphere while utilizing saline or wastewater. These benefits enable microalgae as a potential source for bio-refinery approach. Although life-cycle analysis and economic assessment do not favor the use of microalgae biomass feedstock to produce biofuel and co-products with the existing techniques, this review still aims to highlight the beneficial components of microalgae and their importance to humans. In addition, this article also focuses on current and future aspects of improving the feasibility of bio-processing for microalgae bio-refinery

Chitosan/PEO nanofibers electrospun on metallized track-etched membranes: fabrication and characterization

The development of next-generation adsorption, separation, and filtration materials is growing with an increased research focus on polymer composites. In this study, a novel blend of chitosan (CS) and polyethylene oxide (PEO) nanofiber mats was electrospun on titanium (Ti)-coated polyethylene terephthalate (PET) track-etched membranes (TMs) with after-treatment by glutaraldehyde in the vapor phase for enhancing the nanofiber stability by crosslinking. The prepared composite, titanium-coated track-etched nanofiber membrane (TTM-CPnf) was characterized by Fourier transform infra-red (FTIR), water contact angle, and scanning electron microscopy (SEM) analyses. Smooth and uniform CS nanofibers with an average fiber diameter of 156.55 nm were produced from a 70/30 CS/PEO blend solution prepared from 92 wt. % acetic acid and electrospun at 15 cm needle to collector distance with 0.5 mL/h flow rate and an applied voltage of 30 kV on the TTM-CPnf. Short (15 min) and long (72 h)-term solubility tests showed that after 3 h, crosslinked nanofibers were stable in acidic (pH = 3), basic (pH = 13), and neutral (pH = 7) solutions. The crosslinked TTM-CPnf material was biocompatible based on the low mortality of freshwater crustaceans Daphnia magna. The composite membranes comprised of electrospun nanofiber and TMs proved to be biocompatible and may thus be suitable for diverse applications such as dual adsorption–filtration systems in water treatment

Exploration on Bioflocculation of Nannochloropsis oculata Using Response Surface Methodology for Biodiesel Production

Harvesting of algal biomass in biodiesel production involves high energy input and cost incurred process. In order to overcome these problems, bioflocculation process was employed and the efficiency of this process was further improved by the addition of a cationic inducer. In this work marine Bacillus subtilis was used for bioflocculation of Nannochloropsis oculata and ZnCl2 as cationic inducer. This study worked under the principle of divalent cationic bridging (DCB) theory. Under temperature stress and high pH, the bacterium produced exopolysaccharide that bound with microalga Nannochloropsis oculata and flocculated them. A maximum efficiency of 95.43% was observed with the optimised RSM parameters—temperature 30.78°C, pH 10.8, flocculation time 6.7 h, bioflocculant size 0.38 mL, and cationic inducer concentration 0.035 mM. The present investigation focused on the cost effective harvesting of microalga on a larger scale for biodiesel production than using toxic, ecofriendly chemical flocculants